Richard McKim, Director
email address:
fax and answerphone: 01832-274052
home telephone: 01832-205387

Main B.A.A. Home Page

Choose a date of interest

2001 Opposition

July 16 - August 31, 1999

June 1 - July 15, 1999 | April 16 - May 31, 1999 | March 1 - April 15, 1999 | February 1-28, 1999

December 16, 1998 - January 31, 1999 | November 16 - December 15, 1998 | pre November 16, 1998

June 1-15, 1997 | May 1-31, 1997 | April 16-30, 1997 | April 1-15, 1997 | March 16-31, 1997

March 1-15, 1997 | February 16-28, 1997 | February 1-15, 1997 | January 1-31, 1997

  • 2001 Opposition

    BAA Mars Section Circular 2001 December
    The last Section Circulars were issued during the 1999 apparition. Just this 
    one Circular is being issued for 2001, because Mars has not been well-placed 
    for observation from the UK for the majority of 2001. It is understandable 
    that many found that the planet was simply too low to observe properly at 
    opposition from the UK, which was a great pity due to the large disk diameter 
    at opposition, and to the exceptional planet- encircling dust storm which 
    developed on June 26 and lasted until last month.
    At the moment Mars is relatively high and free from dust, yet almost 
    nothing is being done in the UK apart from my own work. Back to your 'scopes, 
    The following contributed work in 2001, the majority from outside the UK: 
    M.Adachi, G.Adamoli, D.Bates, S.Beaumont, N.Biver, S.Buda, T.Cave, A.Cidadao, 
    E.Colombo, E.Crandall, B.Curcic, P.Devadas, T.Dobbins, K.De Groff, 
    M.Di Sciullo, S.Ebisawa, C.Ebdon, N.Falsarella, M.Frassati, M.Gaskell, 
    E.Grafton, W.Haas, T.Haymes, A.Heath, M.Hendrie, C.Hernandez, T.Ikemura, 
    M.Justice, T.Leong, F.Melillo, C.Meredith, M.Minami, D.Moore, D.Niechoy, 
    B.Pace, P.Parish, D.Parker, T.Parker, D.Peach, C.Proctor, T.Richards, 
    R.Schmude, W.Sheehan, I.Stellas, G.Teichert, D.Troiani, A.Valimberti, 
    A.Gonzalo Vargas and the writer. Thanks to all.
    Review of the 2000-2001 Session
    This was published by the Director in the BAA Journal for 2001 October. As 
    noted therein, there was Mars news in BAA Circulars 777 and 779. It is 
    assumed that all UK members subscribe to the BAA Circulars. This is where 
    brief news of the great dust storm of 2001 was published. There was also a 
    good deal about how to observe, and an early Interim Report, in the Journal 
    for 2001 June.
    The Great Dust Storm of 2001
    Before opposition MGS imaged local dust storms, and one example in Hellas 
    is illustrated in Astron. & Geophys., 2001 August , page 26. The image is 
    dated April 8. There is further MGS evidence of local dust activity in 
    Hellas in mid-June. By late June ground-based observers also detected local 
    activity in Hellas. On the 24th, atmospheric dust was confined within the N. 
    part of the basin, but on the 26th a long, bright, twisting ribbon of dust 
    had extended into Ausonia, marking the emergence of an important event at 
    Ls = 185 deg., right at the start of southern spring. The HST imaged Mars 
    the same day but this activity was beyond the evening limb. Only the 
    slightly dusty nature of Hellas could be seen on the latter image. But MGS 
    temperature data (using the thermal emission spectrometer) show a warming 
    beginning in Hellas on the 24th. The event developed quickly and dust 
    expanded from Hesperia (long. 270 deg.) and Hellas (long. 300 deg.). Leong's 
    image of the 27th shows additional dust in Libya with diffuse dust starting 
    to mask the Syrtis Major and points east. Rapid expansion of the event 
    occurred chiefly to the E. and NE, and additional activity occurred over 
    Elysium. Within a few days the OAA were calling it a 'global' storm, but 
    this is to misuse the agreed classification system. The dust covered much 
    of one hemisphere, true, but in longitudinal extent it was still only a 
    large regional event. Over the next few days Syrtis Major was effaced. So 
    far, this was not much different from the course of many past regional 
    storms such as 1988 June.
    The Director published several letters in the Communications in Mars 
    Observations of the O(riental) A(stronomical) A(ssociation) (Japan): (no. 
    247, 2001 July 10) These give some historical perspective.
    On the night of July 3/4 a significant development began: a new bright dust 
    core appeared in Daedalia in the images of Valimberti. This new storm 
    expanded rapidly, and its incidence showed that a global forcing condition 
    was operating despite the very early seasonal date. Over the next few days 
    Parker and others imaged the new event's expansion primarily to the east 
    over Solis Lacus, Valles Marineris and Mare Erythraeum (etc). Many small 
    new bright clouds appeared around the region. The storm front crossed 
    Noachis to link with the Hellas regional event, and the latter event had by 
    then expanded east to meet the new event around the longitude of Thaumasia/
    Mare Sirenum. By July 11 (storm day 16) the planet was encircled by dust 
    and contrast was low everywhere. Albedo features rapidly faded from view. A 
    pair of HST images for June 26 and September 4 published in Sky & Telesc., 
    2002 January, give a graphic representation of the extent of the dust.
    By mid-July the colour of the planet was more yellow than orange and even 
    to the naked eye the colour was noticeably different. The dust veil 
    extended down to a latitude of about 40 deg. north, so that the north polar 
    hood was not veiled. The NPH became less active in August, though this 
    could be due to the southward movement of the subsolar point. The dust had 
    a significant warming effect upon the martian atmosphere, to the extent of 
    40 K or more between latitude 20 N up to the S. pole, as measured by MGS 
    from orbit. All evidence of white cloud activity was suspended for months. 
    Indeed, even the limb brightening was less sharp and less marked during the 
    Viewed from the Earth it was hard to see what was happening in the far south. 
    The SPC was tilted away from the Earth and the cap, though large, was 
    foreshortened. It appears that dust did not cover the SPC (see the 
    aforementioned HST image for September 4) but nevertheless did extend to 
    rather high southern latitudes.
    During July the only specific bright clouds were over Hellas and also over 
    Daedalia. Several observers reported renewed activity over Daedalia, and 
    this source remained active for some time. In August and September many 
    observers sketched or imaged Olympus Mons as a dusky spot, showing that the 
    storm could not have been much higher than its summit caldera. As Minami 
    points out, the spot represents the caldera making a hole in the 
    surrounding swirling yellow clouds rather than an albedo feature as such. 
    Sure enough, as the dust settled, the caldera became indistinguishable.
    These notes are intended as preliminary only, and do not constitute a full 
    report. From late August onwards a gradual clearing was underway, but it 
    was very slow, and throughout September the ground markings remained hard 
    to see well. By October the general albedo features could be easily 
    recognised, but contrast was not back to normal until mid or late November. 
    Signs of atmospheric dust were even then still detectable: some dust hung 
    over Edom crater and a patch of dust hung over Argyre, whilst Hellas was 
    still bright and yellow. In early December McKim and others still saw N. 
    Hellas to be bright in yellow and red light, but there were no other bright 
    dust clouds. By then all the features were sharp and well-defined, even if 
    some were apparently not as dark as in the pre-storm period, and 
    furthermore the SPC was again well contrasted as the southward tilt of the 
    axis increased, though by then greatly shrunken. The storm had
    lasted a long time, but not quite as long as the truly global event of 1971.
    Historical context
    For a NASA press conference on October 11 at which HST and MGS data upon 
    the great storm were to be presented, Jim Bell (who kindly set up the Mars 
    Section web pages when he was the pro-am Marswatch coordinator) asked for 
    the writer's views about the '2001A' storm. Here is what I emailed in 
    "I think the most important point about the present storm (2001A) is that 
    it was seasonally the earliest ever recorded amongst all the past 
    encircling events. It was also one of the most enduring storms, and 
    optically one of the most dense........... It also may mark the return to 
    the dusty climatic period that was witnessed throughout nearly the whole of 
    the 1970s and into the early 1980s. My historical work clearly established 
    the fact that encircling storms were witnessed every martian year from 1971 
    to 1977. It showed that 1975 contained a planet encircling storm, a fact 
    not widely appreciated, and this year together with 1971 and 1973, when 
    coupled with the Viking data up to late 1977 show the emergence of a great 
    storm every year on Mars (with two in '77). This epoch was unprecedented 
    and Viking's cameras recorded an atypical Mars: a fact well worth 
    reiterating. During this epoch both Hellas and Thaumasia/Daedalia dominated 
    the scene as emergence sites, indeed they remain the only such sites for 
    the emergence of encircling storms.
    "The 2001A event is important in possibly marking a return to dusty 
    climatic conditions: but by definition we shall not know for at least two 
    or three more martian years.
    "The development of the 2001 event was similar to many past great 
    storms........ It began with what appeared to be a large regional event 
    originating in the Hellas longitude. In this respect the storm was not 
    seasonally especially early. Historically, regional storms from Hellas had 
    begun at even lower Ls (see the tables in the BAA Memoir). One more 
    discovery from my book [Mem. Brit. Astron. Assoc., 44 (1999)]. I divided up 
    the last century and a half into epochs: 1866-97; 1898-1929; 1930-61; 1962-
    93. I wrote on page 144 in connection with the Hellas emergence site: "In 
    the last three epochs, the R(egional) type storms have begun progressively 
    earlier in the season." It seems that the 2001A event's timing has also 
    been unusually early. Is there a simple physical mechanism for this 
    phenomenon, associated with the gradual net accumulation of dust grains at 
    a site?
    "Event 2001A became planet-encircling when a secondary source of dust 
    emergence commenced in Daedalia about July 4, and together with the initial 
    dust outbreak carried dust around the globe. All the great storms have 
    become encircling in this way when a secondary source supported the initial 
    outbreak elsewhere: for example, the 1973 event began in Daedalia/Claritas, 
    but it had secondary outbreaks over Hellas and Meridiani Sinus.
    "There is a possibility that the retreat of the SPC began early in 2001: I 
    have made no measures yet, and it is just a possibility. In 1986, the SP 
    hood cleared at Ls 180, but in 2001 the hood was already cleared by then.
    "The 2001A storm showed a more vigorous expansion to the north than some of 
    the most recent encircling events. Thus the area of Syrtis Major was 
    blotted out from view quickly. As to its duration, it is still in
    evidence, though clearly dying out now. Thus its duration will be greater 
    than 15 weeks, or 105 days. It will probably last no more than another few 
    weeks. The durations of the planet-encircling storms of the 1970s-80s dusty 
    epoch were (my data): 1971 161 days; 1973 91 days; 1975 100 days; 1977A 60 
    days; 1977B 158 days; 1982 110 days.
    "For visual observers 2001A was probably the most opaque storm since 1971, 
    although the 1971 storm was more global in its dust coverage. Of course, 
    the 1977 and 1982 Viking data were a little incomplete."
    The MGS data for the 2001A event have been written up in the paper Thermal 
    emission spectrometer observations of martian planet-encircling dust storm 
    2001A by M.D. Smith, B.J. Conrath, J.C. Pearl, and P.R. Christensen and it 
    was recently accepted for publication in the journal Icarus.
    Changes upon the martian surface
    As is usual with big dust storms, some changes upon the martian surface 
    were apparent. Prior to the storm, the markings were much as they had been 
    in 1999. Nepenthes was invisible, Cerberus and Trivium Charontis nearly so; 
    Nodus Alcyonius, the Amenthes darkening and Solis Lacus were all 
    prominent. After the storm, Parker remarked that Syrtis Major appeared 
    thinner, and the writer found it more tapering to the north in his recent 
    work; at the same time, Deltoton Sinus had become more visible. And there 
    was a new dark marking just W. of Solis Lacus, greatly resembling the old 
    'Phasis' canal shown on the maps of G.V.Schiaparelli and N.E.Green from 
    1877. This was imaged from early September onwards, when Solis Lacus itself 
    was still mostly hidden by bright dust clouds. (This feature was also 
    observed during the mid-1980s through the early 1990s.) Solis Lacus itself 
    was smaller after the storm, and the feature known as Nectar, connecting 
    Solis Lacus to Mare Erythraeum was greatly faded.
    The rest of the apparition
    Mars is still very much observable, upon the meridian early in the evening, 
    though he is now only some 7 arcsec across. Work should continue into 2002 
    as far as possible until Mars is lost in the evening twilight. There may 
    even be further dust activity, given that we are still within the martian 
    southern hemisphere summer season, and accurate recording of the size and 
    shape of the SPC is important for comparison with the historical records. 
    The Director is enjoying good views at present, despite the tiny diameter. 
    The markings are clearly defined upon the strongly phased disk, and the 
    planet is crowned by a small SPC summer remnant.
    Publicity for the Mars Section
    The Director gave a talk to the Cambridge University Astronomical Society 
    on November 7th. Affiliated societies such as CUAS have in the past 
    produced useful reports for the BAA planetary (and other) Sections, and the 
    Director would appeal to local society coordinators to do all they can to 
    increase the input of observational data. The very next day, I was in 
    Oxford, presenting a colloquium on the theme of dust storms to the 
    Department of Physics. This gave an interesting opportunity to see the 
    computer modelling of storms being done by the Oxford team comprising John 
    Barnett, Peter Read, Claire Newman, Stephen Lewis and others. It was 
    gratifying to know how helpful they had found the Mars Section Memoir (see 
    below) to be.
    At the Winchester Weekend meeting in 2002 March the Director will present an 
    illustrated talk entitled 'Perihelic Oppositions of Mars', and this will 
    include a full review of the present apparition.
    Mars Section Memoir on Telescopic Martian Dust Storms
    Copies of this book by the writer are still available for sale from 
    Burlington House. Don't delay too long as all copies will ultimately be 
    sold out. This is the only book that exists devoted to the study of dust 
    Telescopic maps
    These can best be found in the above Memoir. The Section continues to 
    recommend the general map of Shiro Ebisawa, with his nomenclature. A 
    simpler general chart is the IAU map by de Mottoni (1957), but it does not 
    always have sufficiently detailed nomenclature. Another good source is John 
    Murray's albedo map given in the latest edition of Norton's Star Atlas. All 
    these maps inevitably become slightly dated as albedo features change, but 
    all represent an 'average' Mars.
    Section Programme
    For non-members of the BAA who read this, our programme and observing tips 
    are featured in the BAA Observing Guide (formerly known as Nature, Aims and 
    Methods), which can be purchased from BAA headquarters. A new edition is 
    being prepared by the writer for 2002.
    Historical note: Landscape Painting, Queen Victoria and the BAA Mars Section
    What do the above have in common? The answer is a man who was called 
    Nathaniel Green. N.E.Green (1823 - 1899) was a famous English amateur 
    astronomer of the late Victorian period. A landscape painter who exhibited 
    at the Royal Academy in London, Green once included Queen Victoria among 
    his pupils. He was one of the founder members of the BAA in 1890, was 
    President 1896-98 and for some years directed its Saturn Section. By then, 
    Green was already famous for his drawings of the planets, having previously 
    published them in the Astronomical Register and in the Memoirs of the Royal 
    Astronomical Society. He is best known for his 'soft-pencil' views of Mars 
    from the island of Madeira in 1877, at a time when Schiaparelli was 
    covering the planet with fine canali. In 1894 the BAA Mars Section Director 
    B.E.Cammell produced a manuscript report which was too long for the Council 
    to publish. Green was prevailed upon to edit the Memoir down to a more 
    acceptable length, and this he did. When he died, Green left his 18-inch 
    mirror to the Association. This was later used at Headley observatory for 
    many years by the Rev.T.E.R.Phillips, mostly for Jupiter and Mars. In 
    recent years it was at Conder Brow with Denis Buczynski.
    For many years I have casually looked for Green's non-astronomical works 
    without success. But a few weeks ago in an antiquarian bookshop in Stamford 
    I came across a lovely copy of a book Green wrote in about 1880 entitled 
    Hints on Sketching from Nature. I knew that Green wrote more than one book 
    upon the subject, but had never seen any examples. This lovely little work 
    about watercolour landscape painting was published by Rowney & Co., the 
    firm who produce all sorts of artists'9 materials, and was intended to 
    encourage art students new to the craft. Indeed, Green had Rowney & Co. 
    print for his own (and BAA members'9) use cards bearing a series of 2-inch 
    diameter planetary drawing blanks, each disk being  ochre-tinted and set 
    upon a black background. You can draw on these disks in pencil or pastel, 
    and then scrape away the ochre tint to give the highlights. I have a stock 
    of these cards in the Mars Section archives, and Richard Baum and I once 
    tried them out.
    The little art book gives beautiful coloured lithographic reproductions of 
    some of Green's works. Oh, to own an original!
    Flowers for Tycho
    My favourite tram ride in Prague is to take tram no. 22 from Malostranska 
    metro station, up the hill to the ancient streets above Prague castle. This 
    route offers lovely views over the city as the tram attacks the steep hill 
    and sharp corners. Then, if you get out at the right stop, you face a 
    large statue of Tycho Brahe and Johannes Kepler. Just behind is the 
    modern Jan Kepler Gymnasium, Prague's top school, and inside there are 
    foundations of a house in which Kepler once lived. Tycho is buried in the 
    Tyn Church in the Old Town Square, a stone's throw from the famous 
    astronomical clock of the Old Town Hall. I have visited the tomb several 
    times and recently I went to see the statue again to mark the 400th 
    anniversary of his death. Czech astronomers had laid flowers there in 
    Tycho's memory.
    And finally......
    Thanks are due to all those who contributed data in 2001. Please be patient 
    with the Director as he slowly prepares the backlog of formal reports for 
    the Journal on the apparitions of 1995, 1997, 1999 and 2001. The 2003 
    apparition will be better than 2001, of course, and we hope to see the 
    Beagle 2 lander arrive in Isidis Planitia to look for evidence of past 
    water in 2003 December or 2004 January..... I look forward to making an 
    early start to that great perihelic apparition!
    Richard McKim, Director
    2001 December 12th; Ls = 289
    Back to Date Menu

  • July 16 - August 31, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 8
    This Circular summarises the period 1999 July 16  (Ls  = 171 deg, D = 10.3 
    arcsec, decl. =  -14 deg.) to August 31 (Ls = 197 deg, D = 7.9  arcsec, decl. 
    = -21 deg.). Mars remained an increasingly difficult evening object, and the 
    last UK observation received is that by the Director  on August 10, observing 
    >from Truro on the eve of the total solar eclipse. The planet has been easier 
    to view from the USA, Italy and Japan, etc. Since the last Circular I have 
    received observations from Parker, Foulkes, Crandall, Di Sciullo, Melillo, 
    Wasiuta, Topping, Teichert, Niechoy, Meredith, Johnstone, Hendrie, Heath, 
    Haas, Grego, Colombo, Adamoli and Frassati, six of whom had not sent 
    observations earlier this apparition. Especially praiseworthy among the 
    visual observations are the series of later drawings by Haas, Frassati and 
    Adamoli, which continue to document the changing polar regions and white 
    MGS  observations 1999 June
    MGS observations of dust activity in the N. polar region on June 30 were 
    released onto the Web on August 10, in other words since the last Circular. 
    The images are dated June 30, 0652h, 0850h, 1047h and 1245h UT, showing the 
    hemisphere of Mare Acidalium. A dust cloud curls southward from near the NPC 
    remnant, concealing Hyperboreus Lacus. (See Extract B from the MGS Website, 
    below.) The Director was not aware of  this event at the time, so he could 
    not alert observers. But the region was on the wrong side of the planet to be 
    viewed from the UK at that time. Japanese observers may have viewed some 
    indications of the event in early July.
    It will be recalled from Circular No. 6 that of the BAA observers, Cidadao 
    and McKim viewed dust activity in the Mare Boreum region on June 2-3, not far 
    >from the event of June 30. This area, adjacent to and NW of the large dark 
    area Mare Acidalium, has therefore produced several small dust events and 
    white ‘cyclonic’ clouds (see an earlier Circular) during the apparition. 
    Historically the region has produced other ‘cyclonic’ clouds during the 20th 
    Century. But what about dust storms? The large albedo and thermal inertia 
    contrasts between Acidalium and the neighbouring classical deserts of Tempe, 
    Chryse, Xanthe has occasionally led to dust initiation in the latter desert 
    regions, but I cannot recall dust activity starting over Mare Boreum during 
    the period reviewed in the Dust Storm Memoir (i.e., up to 1993). This all 
    goes to show that Mars can still surprise us. Past records of a yellowness 
    about the polar regions should therefore not be dismissed immediately as 
    observational error! In the Mars Memoir (see later) I have called attention 
    to such polar dust records, and briefly describe my results. But after the 
    martian polar storms in the summers of 1997 and 1999 it may be prudent to 
    further reexamine some historical data…….
    Extracts from the MGS website
    Herewith some exciting extracts from the Web. Of course, you need to see the 
    pictures! I picked the comments most relevant to the groundbased observer. I 
    have taken the liberty only of improving the spelling on the Website 
    (sorry!), and of adding a few of my own comments in square brackets [  ].
    Extract A
    "Wind Action--The Dust Devils of Amazonis Planitia
    MGS MOC Release No. MOC2-171, 10 August 1999
    Dust devils result from spinning vortices of air that lift dust from a 
    planet's surface. They look something like a miniature tornado. The dust 
    devils shown here were observed in mid-May 1999 in northern Amazonis Planitia 
    (northwest of the Olympus Mons volcano). Dust devils are common in this 
    region and were seen there even during the Viking orbiter missions in 
    The first two pictures (A and B, above [see the Website! - RJM]) show a 
    colour composite view of the Amazonis dust devils as they appeared to the 
    Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) red and blue wide angle 
    cameras; the white arrows in MOC2-171b (B, above) point to each individual 
    dust devil. The third picture (C, above) is a GIF "movie" (Click on the Icon) 
    that shows dust devil occurrences on two different dates in May 1999. The 
    scene in this "movie" is about 88 kilometres (55 miles) across. The fourth 
    picture (D, above) is a diagram that compares the typical heights of dust 
    devils and tornadoes on Earth with dust devils on Mars. Click on the 
    "cartoon" icon to see the entire diagram, including a comparison with the 
    heights of the tallest mountains on Earth (Himalayas) and Mars (Olympus Mons).
    The heights of dust devils in MOC images can be estimated from the length of 
    the dark shadows that they cast. The shadows in these pictures all point 
    toward the northeast (toward upper right). The largest dust devil in these 
    pictures towers nearly 8 kilometres (5 miles) above the martian surface, and 
    has a lower basal plume of dust that suggests substantial surface flow of 
    wind and dust into the rising column. In the MOC images shown here, north is 
    up, and the sun's illumination is from the lower left. The 40 kilometre scale 
    bar also indicates a distance of about 25 miles. Additional MOC images 
    regarding these and other dust devils:
    •"Large Martian Dust Devils Caught in the Act," July 1, 1999. •"SUV Tracks on 
    Mars? The 'Devil' is in the Details," July 30, 1998."
    Extract B
    "Late Summer Storms Over the North Polar Region
    MGS MOC Release No. MOC2-172, 10 August 1999
    Storm clouds have been brewing over the north polar cap of Mars since the 
    last week of June 1999. During the month of July, summer was ending; autumn 
    began at the start of August. The wide angle cameras of the Mars Global 
    Surveyor (MGS) Mars Orbiter Camera (MOC) have been documenting the changing 
    weather patterns of the red planet nearly every day since the Mapping Phase 
    of the mission began in March 1999. These images are showing many more 
    details about martian weather than had been previously recorded. Mars is a 
    dynamic planet, with weather systems as complex and exciting as the Earth's.
    The four still-frame images (above) show the evolution of a storm system that 
    developed over the martian north polar region on June 30, 1999. Each picture 
    was taken approximately 2 hours later than the previous. The north polar ice 
    cap is the white feature at the centre of each frame. Clouds that appear 
    white consist mainly of water ice, clouds that appear orange/brown contain 
    This particular storm system lasted well into the next day--July 1, 1999. A 
    total of 23 red and 23 blue camera images were used to create a time-lapsed 
    "movie" that displays the development and evolution of this storm over the 
    two-day period. Of great interest are the "curling" of the clouds behind the 
    largest of the storms--this indicates a flow vortex that follows the storm 
    front that is moving toward the top/upper right of the frame--and the 
    correlation of white water-ice clouds with orange/brown dust clouds. High 
    surface winds must have raised dust and mixed it with water vapour  in the 
    air over the summer-time polar cap to create this effect. To view the 
    "movie," click or download to your desktop the following 2.2 MByte MPG file.
    Storms similar to those shown here were observed to continue throughout the 
    month of July and into August [unfortunately there are no details given on 
    the Website - RJM]. Over the next several months, the north polar cap will 
    grow dark as the region transitions through autumn and into winter. When 
    northern winter begins in December 1999, this region will be dark and 
    obscured by clouds." [This is not so: the NPH will be a permanent feature 
    well before 1999 December! - RJM]
    Extract C  [quoted in part only]
    "Mars: An Active Planet
    MGS MOC Releases MOC2-166 to MOC2-172, 10 August 1999 
    Among the goals of the Mars Surveyor program are to characterize the planet's 
    climate and the interaction of the atmosphere with the planet's surface. Both 
    the Mars Global Surveyor (MGS, presently in Mars orbit) and the Mars Climate 
    Orbiter (MCO, which reaches Mars in September) address these goals in part by 
    using cameras to observe martian weather and changes on the surface that 
    occur from season to season.
    Mars Global Surveyor has been orbiting the Red Planet for just over 1 martian 
    year (687 days). Although the spacecraft only recently attained its final 
    design orbit after 18 months of aerobraking and other orbit phasing 
    activities, "snapshots" of Mars acquired during this period by the MGS Mars 
    Orbiter Camera (MOC)--when it has been on--and more recent views from the 
    present mapping orbit have captured a unique record of seasonal and 
    meteorological events that demonstrate that the planet is quite active and 
    dynamic today.
    Evidence for present-day activity comes in two forms--weather, and surface 
    changes. Detailed weather observations include the tracking of dust devils 
    and the daily mapping of cloud and storm patterns. Other changes on the 
    planet have been seen among frost-covered sand dunes. These changes are 
    connected to the passage of martian seasons and the retreat of polar ice as 
    winter draws to a close and spring begins. As the winter ice begins to 
    sublime, dunes develop small dark spots that grow and eventually coalesce 
    until the frost disappears. Some dunes show evidence that wind and gravity 
    are actively moving the dune sands, as well.
    The images shown below were presented at a Space Science Update briefing at 
    NASA Headquarters, Washington, DC, on 10 August 1999. For the corresponding 
    JPL Press Release, see: 
    1. The Mystery of the Spotted Dunes
    "Bushes" On Dunes
    August 1999 
    Snow Leopard Dunes
    August 1999 
    Changes In 26 Days
    August 1999 
    Wind Streak Dunes
    August 1999 
    Every year, Mars grows two large, seasonal frost caps (one during each 
    hemisphere's winter) out of a combination of atmospheric carbon dioxide (the 
    major component of the cap) and water vapour. At the end of each winter, 
    these caps recede in latitude as the sun moves across the equator and into 
    the spring-time hemisphere. This annual cycle of frost deposition and 
    sublimation (i.e., the process by which ice transforms when heated directly 
    >from solid to gas without first "melting" to form a liquid) is one of the 
    defining elements of the martian climate. There is much that is unknown about 
    this process, but recent observations of sand dunes within the polar regions 
    are providing new information about the seasonal retreat of the polar ice 
    Observations made in 1998 at the end of the north polar winter showed some 
    evidence that dark spots develop on sand dunes as the winter frost begins to 
    disappear. This year, 1999, similar features have been observed in the 
    southern hemisphere as winter has proceeded into spring (southern spring 
    began August 2, 1999). The evidence from the dunes suggests that defrosting 
    begins more or less simultaneously at many small, localized sites. Each site 
    then grows radially from the initial spot, enlarging and eventually merging 
    until all of the frost is gone. The rate of growth of the defrosted surfaces, 
    and the details of their appearance, indicate that the frost is probably 
    repeatedly sublimed and locally re-deposited, with this local cycle acting to 
    "refrigerate" the ground and moderate or slow the rate of polar cap retreat. 
    Each picture shown above (MOC2-166 to MOC2-169) provides examples of the dark 
    spots that develop on dunes as they "thaw out," including comparisons over a 
    26-day period and an example of local wind transport of sand exposed in the 
    2. Recent Dune Activity
    Proctor Dunes
    August 1999 
    Since first seen in Mariner 9 images of Mars, the isolated dune fields within 
    large impact craters have been of great interest, as their dark colour 
    indicates that the light dust that covers much of the planet does not 
    accumulate on the sandy surfaces. This indicates that the dunes must be 
    active--moving--and that we might, with time, eventually see evidence of 
    changes that allow us to measure the effectiveness of wind erosion on Mars. 
    The dune field in the picture above shows evidence of recent activity, as 
    dark sand has been mobilized and transported across surfaces covered by the 
    late-winter remains of seasonal frost."
    BAA and other observations, 1999 July 16-August 31: mostly concerning the 
    polar regions 
    The OAA (Japan) have reported observations of both the hood and ground cap 
    during July 1-15, the hood predominating, with the situation changeable from 
    day to day and especially with CM longitude. Since the last Circular, further 
    supporting BAA data have come to hand for the first half of July. 
    Observations for the second half of the month continue to show the NPH. 
     Minami writes in OAA Circular No. 221: "This apparition provided a rare 
    opportunity to watch the moment we had after these 15 years since 1984….. We 
    will meet 160 deg. Ls again in mid-May 2001 with apparent diameter 16 arcsec, 
    but the sub-Earth point will be [in] the southern hemisphere." The Director 
    agrees. It is rare to have this opportunity to watch the NPC to NPH 
    transition with favourable presentation and disk size. A well-documented 
    apparition for the transition from ground cap to hood is that of 1905. After 
    re-examining Percival Lowell’s published sketchbook ‘Drawings of Mars, 1905’ 
    in my library, I was struck with the enormous energy of Lowell for examining 
    the planet so frequently. If we ignore the stylised representation of the 
    albedo features, the polar region seems to be very accurately portrayed. The 
    transition from cap to hood that year is also recounted in one of Lowell’s 
    popular books. But despite his 24-in Clark OG, Lowell could only watch at one 
    terrestrial longitude.
    The S. limb has remained bright, though not always at all longitudes. While I 
    am sure that the ground cap must have already formed, it may be overlaid with 
    the hood sometimes, and it is not easy to see with severe foreshortening and 
    bad seeing on the increasingly tiny disk. Some observers refer explicitly to 
    a ground cap. In the longitudes of Argyre and Solis Lacus the SPH was 
    especially bright in July (e.g., Parker’s images of July 21, 24), but more 
    data are needed for August. 
    Again, I do not intend to report upon white cloud activity on the planet 
    The BAA Dust Storm Memoir: status
    By the time this Circular reaches you the delivery of the Mars Memoir will be 
    just a few weeks away. The Memoir will be advertised in the December BAA 
    Journal, the next available issue, and I am hoping Sky & Telescope will 
    mention it.  The draft advert for the BAAJ runs as follows:
    "This new 168-page book by Richard McKim, Director of the Mars Section, gives 
    the first complete narrative account of all the telescopic martian dust 
    storms observed since records began. Many previously unpublished observations 
    by both amateurs and professionals are described and illustrated. The book 
    contains a catalogue, discussion sections, reference maps and charts, and 300 
    illustrations including a portrait gallery of past and present Mars 
    observers. Members can obtain a copy post-free by sending a cheque payable to 
    the ‘British Astronomical Association’ to the Assistant Secretary at our 
    headquarters at Burlington House, Piccadilly, London, W1V 9AG, Great Britain 
    (tel: 0171  734  4145; fax: 0171  439  4629; email: 
    ). The following charges will apply:
    BAA members resident in the UK or Europe:           £10.50
    Non-members, UK or Europe:                  £15.00
    BAA members resident in North America:          $22.00 (airmail)
    Non-members, N. America:                    $32.00 (airmail)
    Those living elsewhere please contact the Office for details of costs."
     Note that the BAA does not accept credit card payments: cheques only. 
    Members may buy the Memoir at a discount; please state whether or not you are 
    a member when  ordering (this will be checked!). For their convenience, 
    purchasers from the USA may send a US dollar cheque. To reserve your early 
    copy of the Memoir, please send payment to Burlington House to arrive not 
    earlier than a month from today. I will be sending out about two dozen 
    complimentary copies: one to each of those who have been especially helpful 
    during this project; I am only sorry that finances do not permit us to give 
    away any more! (I will inform you in advance if you are going to receive a 
    free copy.)
    Once again I should add that the Memoir will be published as hardcopy ONLY, 
    and I shall not be giving permission to make it available on the Internet.
    Reporting data to the Section
    I am always happy to receive CCD images by email. Any URGENT and important 
    drawing can be scanned and sent as an image file, but I do not want to 
    receive routine drawings by email, because the vast majority are sent to me 
    as hard copies, and that is the form I like to compare (and archive) them in. 
    Send mail to Cherry Tree Cottage, 16 Upper Main Street, Upper Benefield, 
    Peterborough PE8 5AN, Great Britain; home telephone 01832-205387; home email (Do not use the former email address for my place of work 
    ( Urgent faxes can be sent to my place of 
    work on 01832-277168. Please note the change of my fax number since the last 
    This is the last Circular for the current apparition!
    Although further data will be much appreciated I do not intend to issue 
    further Circulars for 1998-99 apparition. If something exceptional happens I 
    will try to report it in the Journal. 
    A big thank you to all those who supported the Section this apparition. My 
    congratulations upon your fine observations, which I am now working to get 
    into print! See you all in 2001.
    Richard McKim, Director, 1999 September 24th
    Back to Date Menu

  • June 1 - July 15, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 7
    This Circular summarises the period 1999 June 1 (Ls 147 deg, D  14.2
    arcsec, decl. -10 deg.) to July 15 (Ls 171 deg, D 10.3 arcsec, decl. 
    -14 deg.). Mars has been an evening object, and to see him at reasonable
    altitude from the UK, near the meridian, has meant picking him up against a
    light blue sky. Some of the early June observations were reported already in
    the last circular. Further contributions have come from B.Adcock, T.W.Leong
    and M.Valimberti (CCD images), M.Adachi, D.L.Graham, D.P.Joyce, P.Lyon
    (photos with 20-cm SCT), P.W.Parish, J.D.Shanklin, D.M.Troiani, and A.Van der
    Jeugt. Peter Lyon managed some excellent photos from his site in Birmingham,
    and I am quoting in extenso from his letter of June 21, to pass on details of
    his experiments concerning film and technique. His are the only photos
    received in 1999; last apparition I received photos from just two observers.
    There is no denying the great aesthetic value of a nice planetary photograph,
    and I hope observers will still make them, if only for the sake of historical
    continuity and as a true test of skill. He prefaces his discussion with the
    comment that given the pace of digital camera progress, the details may be
    less useful in 2001!
    Photographing Mars in 1999 by Peter Lyon
    "Exposure lengths: The criteria will differ with every telescope/camera set
    up, but on my portable C8 SCT I have found that in an exposure of 2 seconds
    or more the initial vibration (about 0.3 seconds) due to the camera shutter
    does not show up. For Mars at image scales above f/100 this usefully is the
    exposure required anyway on colour slide films which are sufficiently fine
    grained to record fine detail. I favour 2 second exposures to avoid
    excessively precise polar alignment, which are short enough to test for
    vibration on the Mon even without a special lunar drive rate.     
    Films: Initial tests on Agfachrome RSX 50 Professional colour slide film
    simply served to confirm an exposure for Mars of 2 seconds at f/110 (from
    UK), but the film although giving good colours seemed to lack contrast and
    was far too coarse-grained for Martian detail. Kodachrome 25 at f/110 and 4
    seconds exposure gave good contrast, fine grain and a vivid green colour (for
    Mars!), so was definitely not suitable. Kodachrome 64 at f/120 and 2 seconds
    exposure perhaps suffers somewhat from reciprocity failure. The grain, while
    coarser than the Kodachrome 25, was reasonably acceptable but the colours are
    (not surprisingly) those of 'old' Mars photos - a pinkish hue for the desert
    areas and a mauve tint to the dark markings (which have reasonable contrast).
    Fujichrome Velvia (50 ISO) at f/110 and 2 seconds exposure must, for theis
    selection of films, be regarded as the definitive film for Mars. The colours
    are recorded, with no hint of any shift in colour balance, precisely as a
    pleasant orange hue for the deserts with quite neutral dark markings and the
    smoothness of very fine grain completely surpasses both of the Kodachromes. I
    have no doubt that this film, at this image scale, could record all detail
    that the telescope can resolve, without resort to high contrast
    black-and-white films. The contrast of the Fuji Velvia, although not
    dramatic, is well up to the task and is quite amenable to enhancement by
    slide duplication techniques."
    BAA and other observations, 1999 June 1 - July 15: mostly concerning the polar 
    regions I have carried the observations up to July 15 in order to document the 
    most interesting phenomenon of the moment: the appearance of the N. polar hood.
    Signs of a permanent polar hood mark the late June observations, and
    occasionally before that time. In Circular No. 6 the 'polar cyclone' of HST
    was described: such large white clouds are often seen as a precursor to the
    formation of the hood. Two further events were witnessed by members of the
    OAA in May and June.
    Several observers in late June portrayed the cap as being diffuse at the
    edges, and sometimes less bright than earlier on. The latest CMO (OAA) No.
    220 to reach the Director describes the period June 1-15 as observed from
    Japan. As late as June 14th Olympia and Rima Borealis were still visible.
    During all that period the NPC was observed. On June 18 (Ls 157 deg.) under
    CML 322-338 deg. the Director found the S. edge of the NPC less sharp and the
    cap slightly less bright. The NPC seemed sharper on the 20th under CML
    295-298 deg., but seeing was mediocre only. And on the 24th, CML 259-267
    deg., there was a cap with brighter haze to its south. Bad weather then
    intervened. Using Michael Hendrie's 15-cm OG on July 9 (Ls 167 deg., CML 
    96 deg.) the Director had an excellent view, when a definite change in the
    aspect of the area was evident; the slightly less bright hood was larger and
    somewhat diffuse over the N. limb. He found the hood brighter and a little
    larger still on July 11 under CML 86 deg. My later observations constantly
    show a hood.
    Meredith's sketches suggest an increase in the size of the NPR in late June:
    an overlying hood forming? Elisabeth Siegel, June 19, CML 302 deg: "It
    seems to me that the NPC has grown a little bit since the beginning of June"
    And Teichert on June 17-28 found the NPC faded, and blurred at the edges. The
    combined work of Cidadao and Parker seems to show a polar hood present during
    June 25 to July 7. In 1999 the hood has therefore appeared to cover  the cap
    entirely by early July. (Ls 163 deg. on July 1.) The receipt of further
    data will enable these limits to be refined later. In any case, this is
    typical seasonal behaviour. In 1984 the hood appeared at Ls approx. 161 deg.,
    for instance, though it was not constant at all longitudes to begin with.
    At the same time, throughout June and July we have had a very bright S. limb,
    which exhibits still brighter patches from time to time. Especially bright
    parts are those corresponding to northward incursions over Hellas, SW
    Thaumasia (or Claritas) and Argyre. This entire area is foreshortened and
    hard to observe well except in very good seeing. My impression is that it is
    (at least from July onward) now the ground cap, showing as it does a fairly
    sharp N. boundary: I have not yet tried to analyse the precise transition
    from one to the other. (In the past, I have looked for the visibility of the
    cap in red light, while the brighter patches within the hood have been taken
    as signs of the ground cap showing through. More data please!) In 1984 the
    SPC was present from about Ls 161 deg., at the same time as the NPH covered
    the NPC, in fact.
    No certain reports of dust activity have come to hand. No changes in the
    surface features have been detectable upon the rapidly shrinking disk.
    Reports of white clouds continue to be received, but I do not intend to
    describe them further here, suffice to record that the ECB appear to have
    finished, and cloud activity generally, except in the polar regions, seems
    less prominent.
    The BAA Dust Storm Memoir:status
    The BAA Dust Storm Memoir is now in press, the corrected proofs having been
    returned to the printers a few days ago. Watch this space! For now, here is
    the Abstract of the Memoir:
    The dust storms of Mars have fascinated the planetary observer since the
    first observed planetwide event of 1909. To an extent predictable, but
    notoriously variable in amplitude, the dust storms appear as orange, yellow,
    or yellow-white clouds, best imaged in red light. Today, the majority of
    telescopic events are still discovered by amateur astronomers. Apart from
    colour, dust storms exhibit motion and obscure underlying albedo features.
    Temporary, anomalous darkenings associated with yellow clouds arise from the
    removal of the thin surface veneer of dusty material to expose darker
    bedrock. Dust movement also accounts for all long-term albedo changes of the
    classical martian surface markings. The present work, the result of a
    wide-ranging survey of the literature since 1659 and much unpublished
    archival material, identifies dust storms as early as 1704 and as late as the
    1990s, but the timecourse of such phenomena has been followed effectively
    only from the late 19th century.
    The following account draws heavily upon the published and unpublished work
    of the BAA Mars Section (1892 onwards). The records for 1922-39 and 1943-54
    have been analysed for the first time, and the entire archive re-examined. A
    coordinated narrative account of the dust storms observed during every
    martian apparition has been produced, so attempting to collate for the first
    time all the work of the diverse observers and groups. It chronicles the
    dates, extent and movements of observed yellow clouds (and suspected yellow
    clouds and obscurations), and provides comprehensive references to the
    telescopic literature. In the latter respect, the author has tried to cite
    all relevant telescopic studies conducted since 1901, the limit of
    Flammarion's great two-volume work on the planet. Comprehensive narrative
    accounts of many newly recognised regional storms, and of the encircling
    storms of 1909, 1924, 1956, 1971, 1973 and 1975 are published here for the
    first time. A contemporaneous review of the major albedo changes on the
    planet has identified past dust storm sites, even where the storms themselves
    were not directly observed. Many new minor events have been detected, whilst
    in reviewing the extant catalogues, numerous spurious 'events' have been
    shown to be records of limb or polar haze, white cloud, observational errors
    or duplicate records of the same event.
    The account closes with a revised dust storm catalogue, a complete location
    map, and histograms and statistical analyses of the data. This new study
    confirms that there are 'preferred' emergence sites which vary with time.
    Hellas features largely in the statistics for the epoch 1909-1988, with the
    Libya-Isidis emergence site being of major importance up to 1958/59. It is
    shown that despite the less complete temporal coverage before the 1890s, the
    18th and 19th centuries genuinely appear to have been deficient in major, or
    encircling storms. It will be important to continue the ground-based record
    for many years in order to improve our statistics of all types of yellow
    The Memoir will be published as hardcopy ONLY, and there is no intention to
    make it available on the Internet.
    Other recent publications
    * Don Parker et al. describe the ALPO 1997 observations in Icarus, 138, 3-19
    * Ted Stryk published his observations of 1996 January, when significant dust
    activity was inferred from the CO microwave data of R.T.Clancy, in J. Assoc. 
    Lunar Planet. Obs., 41 (2), 76-77 (1999).
    * Paolo Tanga has written up the UAI's 1995 Mars work in l'Astronomia, 1999,
    No. 1, pp 2-11.
    Reporting data to the Section
    I am always happy to receive CCD images by email. Any URGENT and important
    drawing can be scanned and sent as an image file, but I do not want to
    receive routine drawings by email, because the vast majority are sent to me
    as hard copies, and that is the form I like to compare (and archive) them in.
    I have to again write that I am spending a disproportionate amount of time
    downloading files sent to me over the Internet, then decoding, analysing and
    refiling them in the Section's records! Send mail to Cherry Tree Cottage, 16
    Upper Main Street, Upper Benefield, Peterborough PE8 5AN, Great Britain; home
    telephone 01832-205387; home email (Do not use the former
    email address for my place of work ( Urgent
    faxes can be sent to my place of work on 01832-274052.
    The next Circular
    The apparition is all but over for UK observers, given the low altitude and
    small disk size combined. I will therefore issue just one more circular this
    apparition. So let me have your July and August observations by September 15,
    so that the final circular can be issued later that month. Of course, do keep
    trying to observe even longer if you can, and send in your results whenever
    The future reports of the BAA Mars Section
    Although preliminary accounts of the 1995, 1997 and present apparitions have
    been published, final reports have yet to be completed for all these years.
    If anyone reading this has good data for any of these years, but has not yet
    submitted it, please do so now. With the completion of the Memoir, I shall be
    working on final reports on 1995, 97 and 99 during the autumn.
    Good observing!
    Richard McKim, Director, 1999 July 18th
    Back to Date Menu

  • April 16 - May 31, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 6
    This Circular summarises the period 1999 April 16 to May 31 (Ls 130 to 147
    deg). The planet was at opposition on April 24 (Ls  129 deg., D 16
    arcsec., lat. of centre of disk  18 deg. N, decl. -12 deg.). By May 31, D
    had decreased to  14.2 arcsec., and at the time of mailing this Circular D
    has fallen to just over 12 arcsec.     
    The UK weather has remained unhelpful on the whole: compare the number of
    clear nights in 1999 with the splendid weather near opposition in 1997, when
    Comet Hale-Bopp was well-placed. Personally I have managed only 40 drawings
    with my 22-cm reflector. But this is the busiest time of the academic year
    for me, and although I am grateful for having received a deluge of post and
    email, it has not always been possible to reply at once: most of my time has
    been spent in merely filing away the data to look at later! In addition to
    those observers listed in Circular No. 5, I am grateful to Paul Abel, Tom
    Cave, Antonio Cidadao, Maurizio Di Sciullo, Colin Ebdon, David Fisher,
    Maurice Gavin, Michael Hendrie, Henk Munsterman (via Wim Cuppens), Terry
    Platt (via Maurice Gavin), Elisabeth Siegel, David Storey and Myron Wasiuta
    for sending me observations. Apologies to anyone I have forgotten. Michael
    Hendrie's sketches (15-cm OG) are very good representations of the planet's
    features, and Johan Warell made excellent use of a 16-cm apochromat.
    Australian planetary coordinator Bary Adcock sent excellent CCD images by 
    Stefan Buda and Bratislav Curcic (25-cm Dall-Kirkham Cass.). Antonio Cidadao
    (Oeiras, Portugal, 25-cm refl.) and Maurizio Di Sciullo (Coconut Creek,
    Florida, USA, 25-cm refl.) have sent amazing colour CCD images, and
    Maurizio's can be seen in the July issue of Sky & Telescope, page 124. Jean
    Dijon's monochrome ones, secured from his observatory in France, are superb
    too, but most other European images have evidently been limited by less
    favourable seeing conditions.
    Antonio Cidadao's images seemed so good that I asked him if he enjoyed
    excellent seeing. In fact he does not, but he does have some extensive
    experience in image processing, so here are his remarks which may be helpful
    to others:
    "I did begin to obtain CCD images in 94, but the only camera I had at that
    time was not the best to get planetary photographs (a ST6, with large
    pixels). Nevertheless, I did obtain some images for pictorial purposes, and
    to optimize a technique that would allow me to get the best resolution I
    could. You can take a look at a first version of that technique (I still use
    it now) at my Geocities page
    ( I later on
    found out that such manual "super-resolution" approach from under-sampled
    images was nearly identical to that applied by Tim Parker from the JPL to
    process the Pathfinder lander camera images.  Since then I have been in
    contact with him. So, I must tell you that I do NOT have 'super' seeing
    conditions : I wish I had. In fact I work from a 'roof-top' window
    observatory that heats up considerably during the day and is surrounded by
    some 3 or 4 'active' fireplace chimneys. Believe me, I can tell the
    difference when people start to use them during the winter. What happens is
    that I try to fight a lot to get the best possible resolution by averaging a
    lot of registered frames. For instance, for each final filtered component of
    my Mars images I average some 30 to 50 original images (about 15 for Jupiter
    since it does rotate faster). That's a lot of processing to do but it does
    seems to work..." It certainly does!
    MTO-II in Icarus
    Mars Telescopic Observations-II: this was the course the Director attended in
    1997 in Tucson, AZ. Some papers from the proceedings have now been formally
    published in Icarus, 138 (1), 1999 March. I would appreciate reprints from
    any authors reading this Circular!
    New global topgraphic Mars maps
    John Rogers reports that some excellent coloured maps have appeared in
    Science (284, 1495) in June, and have also been placed on the MGS website.
    News from the HST
    In a recent Marswatch electronic newsletter there was some reference to the
    HST work. As has been noted previously in these Circulars, Hubble has been
    taking very few images this apparition. Here is the relevant extract:
    "HST Mars observations: April 27 through May 7
    All of the planned Hubble Space Telescope (HST) observations of Mars for this
    opposition have now been scheduled. HST will observe Mars at four central
    meridian longitudes (for full global coverage) between April 27 and May 7
    (hopefully the recent failure of one of the HST gyros will not hinder this!).
    The exact times when HST will be observing Mars are indicated in the table
    below (times are given in Greenwich Mean Time or Universal Time, which is
    currently four hours ahead of U.S. Eastern Daylight Time).  I am organizing 
    these observations, and I am *especially*  interested in obtaining supporting
    groundbased CCD images from amateurs and professionals during the times when
    the STIS instrument (Space Telescope Imaging Spectrograph) will be observing
    Mars. For the times when STIS is observing, we need high quality CCD images 
    especially in the blue, so that we can determine where clouds, hazes, and
    fogs are most likely interfering with our spectroscopic measurements. If you
    are able to observe Mars in the blue at these times, we would greatly 
    appreciate receiving copies of your images and their descriptions! We will be
    posting the HST images onto a Web site as soon as we get them  processed.
    1999 HST Mars opposition observations 
    Visit  Instrument     Start Time (GMT)         End Time (GMT)
      1      WFPC2      Apr 27 1999 17:55:38    Apr 27 1999 18:51:12
      2      STIS       Apr 27 1999 19:32:20    Apr 27 1999 23:23:27
      4      WFPC2      Apr 28 1999 00:22:25    Apr 28 1999 01:17:59
      7      WFPC2      May  1 1999 13:47:34    May  1 1999 14:43:08
      8      STIS       May  1 1999 15:24:53    May  1 1999 19:14:14
      5      WFPC2      May  6 1999 11:28:10    May  6 1999 12:22:14
      6      STIS       May  6 1999 13:04:18    May  6 1999 16:51:20
      3      STIS       May  7 1999 06:52:54    May  7 1999 10:55:14"
    As BAA data cover every date during April and May, no doubt at least some of
    our observations will coincide with the HST images. Members having CCD images
    close to the above times are invited to send Dr Bell duplicate copies, if
    they have not already done so.
    Mars Global Surveyor News
    MGS is very active, and plenty of new images have been posted on the WWW. The
    Marswatch newsletter also contained a paragraph about the status of MGS:
    "Update on the Mars Global Surveyor Antenna Glitch
    On April 15 the Mars Global Surveyor spacecraft experienced an "anomaly"  (a
    glitch) with its main high-gain antenna. Apparently one of the hinges on the
    high gain antenna got stuck, meaning that the antenna can only swing in one
    direction instead of in two directions. JPL engineers are  troubleshooting
    the problem, and mapping has been put on hold. The plan is to continue
    mapping next week because high speed communications with Earth can still work
    for now even if the antenna can only move along one axis. Check out the April
    23 and earlier updates for many more details:
    Also, check out some of the spectacular early mapping data at:"
    BAA , HST and MGS observations April 16 to May 31
    I have sometimes gone a little way into June in order to continue the
    1.1 Surface features
    Fine surface details have been imaged and sketched throughout the period
    under review, but as mentioned earlier, these details are closely similar to
    1997, even at the resolution of the HST. Gray caught the dark patch inside
    the Huygens crater, which lies in W. Iapigia. With the better resolution near
    opposition some observers were able to detect the little feature Gallinaria
    Silva, the 'oasis' following Solis Lacus which I use as a sort of  indicator
    for secular change in the region. It was inconspicuous. During the last
    opposition it appeared from Parker's CCD images that part of the following
    (W. areographic) side of Solis Lacus was fading a little. This fade has not
    continued during the current apparition, and Solis Lacus therefore remains
    unusually large and dark.
    A few observers noted the apparent martian colours. Amongst them was
    P.Devadas (Madras, India, 36-cm refl.) who on April 20 found M. Acidalium
    grey compared with the bluish-green tint of the S. markings under CML  57
    deg. This difference in apparent colour between the N. and S. markings has
    been remarked upon before. On May 23 Frassati found Propontis (I) to be dark
    brown. (This was also Masatsugu Minami's finding, in April.)
    1.2 White clouds
    Equatorial Cloud Banding seemed progressively less prominent during the
    period reviewed, though traces of it were still present in the longitudes E.
    of Syrtis Major in early June. On mid-disk the bluish 'Syrtis cloud' has been
    seen in the evening and morning, though smaller by late May than in April or
    earlier, and not lasting as long into the martian day. With the decline of
    equatorial white cloud generally, Syrtis Major was easier to see in violet
    light. Ophir-Candor often showed up as a bright streak on mid-disk.
    The SPH has seemed bright, progressively becoming more or less continuous
    across the S. limb, enveloping Phaethontis, Electris, Eridania, Ausonia,
    Hellas, southern Noachis, Argyre and southern Thaumasia/Mare Australe. Hellas
    itself was not as bright as earlier in the apparition according to the OAA.
    The OAA commented on the diurnal behaviour of the Thaumasia cloud, as seen on
    April 16: Minami found brightness S. of Solis Lacus at CML  68 deg; the
    bright cloud passed the CM during CML about 78 to 87 deg; under CML  98 deg.
    the cloud was seen to be occupying Daedalia; under CML  109 deg. the W. end
    of the cloud passed the CM. In Parker's early June CCD images the polar hood
    was constant in latitude across southern Thaumasia and environs at these
    Morning and evening clouds appeared over Libya-Isidis (related to the Syrtis
    cloud). Chryse-Xanthe remained bright in a.m. or p.m., though by early June
    this activity had declined. Small morning and evening clouds were imaged over
    Tempe in April and May. The diurnal clouds over Elysium continued to appear,
    though they were much less prominent towards the end of the period reviewed.
    (On June 10 Parker drew attention to the decline of the orographics in an
    email.) A set of observations was made by Minami in the first half of May to
    show the daily changes in thick morning mist over Utopia.
    Many observers do not send comments with their CCD images. As an example of
    what might be written, here are Di Sciullo's notes, in part, for his May 3
    images, which relate chiefly to the large number of white clouds then imaged:
    "Equipment: Excelsior Optics E-258 10" (25 cm) f/8 Newtonian using eyepiece
    projection @ f/47 Starlight Xpress HX-516 CCD camera, True Technologies
    Dichroic Filters + IR block. No dark frame, flat fielding or bias correction
    applied. Camera operated in "Binned" (low-res) mode.  Seeing:  Mediocre-Fair;
    4-5/10.  Low  humidity (~ 60%), north wind at 3-6 knots. Integration Times:
    610 - 720 nm: 0.20s; 490 - 590 nm: 0.14s; 400 - 510 nm: 0.19s. All images
    acquired with 700 - 1200+ nm block filter in line with eyepiece projection
    unit. Significant activity in 400 - 510 nm band.  Heavy evening haze over
    Xanthe Terra, south to Margaritifer Sinus.  Northern extent of haze appears
    to be southern limit of Mare Acidalium, or approximately Chryse Planitia
    area, at roughly same parallel as Viking 1 landing site.  Haze is triangular
    in shape, coming to a point at an area between Ascraeus Mons, and Hebes
    Chasma. Spot cloud observed at this location, north of Valles Marineris and
    Syria.  Second area of pronounced limb haze showing over Aonia, arcing to
    eastern Mare Sirenum. 400 - 510 nm band also showing cloud bank over Tempe
    Terra / Acidalia region, along with another bright cloud over extreme
    northern Acidalia.  Persistent cloud or detached ice cap still present at
    perimeter of Olympia Planitia, at extreme northern latitude.  Other spot
    clouds showing over Alba Patera, a pair over Ascraeus Mons, and a faint spot
    over caldera of Olympus Mons.  Shield of volcano showing as 'bull's eye' just
    west of meridian, demarcated by slight circular darkening in 400 - 590 nm
    range, punctuated by central bright spot in mentioned bands.  Final faint
    hint of morning haze present over Orcus Patera. Odd cloud, dusky blue-green
    in color observed near 52 north latitude, 202 longitude, just north-west of
    Propontis Complex, and due north of Elysium Mons.  Not likely to be a
    processing artefact, as careful attention was paid to correct color balance".
    1.3 Yellow clouds (dust storms)
    MGS returned further interesting observations, including some signs of dust
    in W. Valles Marineris, near Melas Lacus: see section 3 below for complete
    details. Part of southern Chryse was definitely light in red light on a
    number of occasions, and sometimes Chryse was visually yellowish (e.g., to
    Warell, May 5, 6 on the morning side of the disk). Although there was no
    large event there, small-scale dust activity, perhaps persisting from earlier
    in the apparition, seems the inevitable conclusion. In red light (W25 filter)
    Cidadao imaged a small bright cloud close to the NPC over Mare Boreum on June
    2 (near the CM, with CML  92 deg.). Invisible in the blue images, it had
    become more extended to the SE (areographic; e.g., Sp.) towards Baltia by
    June 3, and may have persisted a few more days. Nothing of the sort had been
    imaged by Cidadao on June 1, albeit under poorer conditions. Observing on
    June 3 McKim confirmed the light detached area imaged by Cidadao. It is
    provisionally concluded that there was a small dust cloud over Mare Boreum;
    it was smaller than the 'HST polar cyclone' (due to white cloud; see below),
    and closer to the polar cap. (Without proper filtration the situation about
    the cap can easily become confused by the bright areas of white cloud
    sometimes surrounding the NPC, these being parts of the newly forming N polar
    hood. These latter areas are brighter in blue light.)
    The OAA Communications In Mars Observations No. 217 (1999 May 10) reported
    still another yellow streak associated with Valles Marineris. On April 16
    under CML 48-58 deg. in good seeing Minami (20-cm OG, Fukui City Observatory,
    Japan) found a light (but not brilliant) yellowish slit streak which
    separated Margaritifer Sinus from Mare Erythraeum. After a hiatus caused by
    bad weather, OAA observer Akutsu imaged a faint segment between Erythraeum
    and Eos on April 20.
    I also received yellow cloud alerts for Tempe (more than one observer),
    Arcadia and Cydonia, and am still assessing the data to see if the
    timecourses of any phenomena may be detailed. At the same time I get the
    distinct impression that too many observers are trying too hard to discover
    dust storms!
    1.4  North polar region
    The NPC remained static in size, as far as could be seen without making
    precise measurements. Hyperboreus Lacus was large and dark. Chasma Boreale
    was seen visually by Tom Cave, Warell and others, and Olympia was widely
    reported or imaged throughout the period under review. Around the cap the
    amount of polar haze increased, so that sometimes the NPC had a more diffuse
    whitish surround. This was especially noticed  by Walter Haas, Mario Frassati
    and the Director. At other times and longitudes discrete bright spots of
    polar cloud were seen, and MGS images were released in both static and movie
    format showing the motions of some wispy streaks about the NPC remnant. The
    HST imaged what the Space Telescope Institute Press Release termed a 'polar
    cyclone' on April 27 (see section 2 for details). There was also a smaller
    dust cloud near the NPC (see section 1.3).
    2. Hubble's 'polar cyclone', April 27
    HST observations of the so-called 'polar cyclone' were obtained on April 27,
    and were described by the following Press Release (STScI-PRC99-220) dated May
    19. (Figure references are to pictures on the WWW page):
    "Hubble Views Colossal Polar Cyclone on Mars
    [left]: Here is the discovery image of the Martian polar storm as seen in
    blue light (410 nm). The storm is located near 65 deg. N latitude and 85 deg.
    W longitude, and is more than 1000 miles (1600 km) across. The residual north
    polar water ice cap is at the top of the image. A belt of clouds like that
    seen in previous telescopic observations during this Martian season can also
    be seen in the planet's equatorial regions and northern mid-latitudes, as
    well as in the southern polar regions. The volcano Ascraeus Mons can be seen
    as a dark spot poking above the cloud deck near the western (morning) limb.
    This extinct volcano towers nearly 16 miles (25 km) above the surrounding
    plains and is about 250 miles (400 km) across.
    [upper right]: This is a color polar view of the north polar region, showing
    the location of the storm relative to the classical bright and dark features
    in this area. The color composite data (410, 502, and 673 nm) indicate that
    the storm is fairly dust-free and therefore likely composed mostly of water
    ice clouds. The bright surface region beneath the eye of the storm can be
    seen clearly. This map covers the region north of 45 degrees latitude and is
    oriented with 0 degrees longitude at the bottom.
    [lower right]: This is an enhanced orthographic view of the storm centered on
    65 deg. N latitude, 85 deg. W longitude. The image has been processed to
    bring out additional detail in the storm's spiral cloud structures.
    The pictures were taken on April 27, 1999 with the NASA Hubble Space
    Telescope's Wide Field and Planetary Camera 2.
    Credit: Jim Bell (Cornell U.), Steve Lee (U. Colorado), Mike Wolff (SSI), and
    This event was also the subect of a strange note in BAA Circular 771, in
    which it was unfortunately described as a dust storm. The note did not
    originate from the Director, who had not been consulted about it. So what did
    the ground-based observers actually see?
    I received several images and sketches which showed this phenomenon,
    including one by myself on April 27, when I found Iaxartes invisible, and the
    area between Hyperboreus L. and M. Acidalium to be light. The same day, Cliff
    Meredith caught the cloud on a (low resolution) CCD image. The best
    ground-based image I have received is due to Cidadao, who caught the cloud on
    April 28 under a CML of 88 deg., when it had become a less impressive E-W
    whitish streak. Remnants of what may have been the same cloud showed up on
    his May 3 image (CML about 119 deg.), though by then the identity of the
    white patches had become questionable. This longitude band was not observable
    from the USA at the critical time, but the Japanese observers could catch the
    E. end of the  phenomenon on the morning side of the disk. OAA observers
    established that morning cloud over Baltia, between M. Acidalium and
    Hyperboreus Lacus, developed from April 25 onwards; they were able to follow
    the phenomenon till the 29th.
    Such polar clouds have been known for many years of course; ground-based
    observations of identical features were made in 1997, for example. What was
    exceptional in the present case was the resolution achieved in the HST images.
    3. MGS views  dust  in Valles Marineris
    Amongst the more breathtaking images released onto the WWW site by MGS, there
    has been an image dated May 16 showing atmospheric dust in the Valles
    Marineris. It will be recalled that this site has been active twice already
    this apparition (see earlier Mars Section Circulars). Given the chance
    viewing of any single site by the MGS cameras, it seems unlikely that it
    would catch a storm at its onset. Perhaps more likely is that the billowing
    dust was raised from the latter of the two previous events, and was imaged
    slowly settling rather than rising. MGS only shot one image on one date, so
    no more can be concluded. None of this small-scale detail could be seen by
    the BAA team, so the activity was too small to be viewed from Earth: though
    Don Parker and others turned in fine detailed CCD shots of the albedo
    features and large-scale diurnal clouds around the Valles Marineris, these do
    not show any fine-scale tonal differences in the canyon system during May. In
    particular, Don's images revealed no changes there during May 3 to 14. After
    May 14 our colleague from Florida lost the area at the morning terminator.
    Nothing was reported by any ground-based astronomers. Here is the full text
    from the WWW site:
    "May 1999 Dust Storm in Valles Marineris: MGS MOC Release No. MOC2-130, 27
    May 1999
    Mars Global Surveyor's (MGS) Mars Orbiter Camera (MOC) captured this view of
    a dust storm within the Ius and Melas Chasms of the Valles Marineris trough
    system on May 16, 1999.
    The dust storm is seen in the lower 1/3 of the image. It occurs at the
    junction between eastern Ius Chasma and western Melas Chasma. The apparent
    motion of the storm is approximately from the south (bottom of image) toward
    the north. The dust cloud forms a sharp front along its northern margin,
    which is seen along the north wall of Ius and Melas Chasms---in fact, at the
    time the image was taken, the dust had advanced up over the north wall of
    Melas Chasma (upper portion of lower right third of image) and was advancing
    across the upland that separates this chasm from western Candor Chasma. For a
    clear-atmosphere view of western Candor and Melas Chasms, see 'Western Melas
    and Candor Chasms, Valles Marineris, MOC2-105, 25 March 1999'.
    For scale, note that the large crater south of Hebes Chasma, Perrotin, is
    about 95 kilometers (59 miles) across. Bluish-white clouds in the image are
    interpreted to consist of water ice. The pink/red clouds of the dust storm
    occur closer to the ground, at a lower altitude than the water ice clouds.
    One of the most interesting aspects of this dust storm is that Valles
    Marineris was observed to have a dust storm at exactly the same time of year,
    one Martian year ago. During its approach to Mars, MOC obtained a picture of
    the planet on July 2, 1997, just prior to the Mars Pathfinder landing. At the
    time, it was winter in the southern hemisphere, and dust clouds were observed
    within Valles Marineris. The picture is seen in "Mars Orbiter Camera Views
    Mars Pathfinder Landing Site, MOC2-1, 3 July 1997". It will be interesting to
    see if similar storms occur within the Valles Marineris 1 and 2 Mars years
    hence. The next times will be in early April 2001 and mid-February 2003."
    The BAA Mars Dust Storm Memoir
    I am now busy correcting the first proofs, and the printers hope to publish
    by early August. It is hoped that the next Circular will contain details of
    price, ordering information and a copy of the Contents page. An advertisement
    will appear in the BAA Journal. I am very pleased with the appearance of the
    text and colour cover.
    Past Reports of the BAA Mars Section
    I am sometimes asked for details of these reports, so it may be useful to
    give the information here. This information, together with a complete guide
    to the telescopic literature for 1659 to 1993, will also be published in the
    Memoir. (I suspect my nice tidy columns will become scrambled in the emailed
    version of this Circular!)
    (JBAA  J. Brit. Astron. Assoc.; MBAA  Mem. Brit. Astron. Assoc.  * 
    preliminary report; **  brief note(s) only)
    Year of oppositionCompiler(s) of reportReference(s)
    1892E. W. Maunder*JBAA, 3, 49 (1892)
    MBAA, 2, part 6 (1895)
    1894B. E. Cammell*JBAA, 5, 148 (1895)
     B.E. Cammell & N. E. GreenMBAA, 4, part 4 (1896)
    1896E. M. Antoniadi*JBAA, 7, 54=9655 (1896)
    *JBAA, 110=96114, 245=96248 (1897)
    MBAA, 6, part 3 (1898)
    1899E. M. Antoniadi*JBAA, 9, 156=96158, 367=96371
    MBAA, 9, part 3 (1901)
    1901E. M. AntoniadiMBAA, 11, part 3 (1903)
    1903E. M. AntoniadiMBAA, 16, part 4 (1910)
    1905E. M. AntoniadiMBAA, 17, part 2 (1910)
    1907E. M. Antoniadi*JBAA, 18, 398 (1908)
    MBAA, 17, part 3 (1910)
    1909E. M. Antoniadi*JBAA, 19, 427 (1909)
    JBAA, 20, 17, 22, 25, 78,
    136, 189, 192, 469, 525 (1909=9610)
    MBAA, 20, part 2 (1915)
    1911E. M. Antoniadi*JBAA, 22, 452 (1912)
    MBAA, 20, part 4 (1916)
    1914E. M. AntoniadiMBAA, 21, part 3 (1919)
    1916E. M. AntoniadiMBAA, 21, part 4 (1920)
    1918H. Thomson*JBAA, 29, 44 (1918)
    MBAA, 26, part 1 (1924)
    1920H. Thomson*JBAA, 32, 48, 86 (1921)
    MBAA, 27, part 1 (1927)
    1922W. H. SteavensonJBAA, 32, 330 (1922)**
    (See note 1.)
    1924W. H. Steavenson JBAA, 34, 348 (1924)**
    (See note 2.)
    1926W. H. Steavenson JBAA, 36, 324 (1926)
    JBAA, 37, 344 (1927)**
    JBAA, 39, 145 (1929)**
    (See note 3.)
    1928W. H. Steavenson JBAA, 39, 145 (1929)**
    (See note 4.)
    1931B. M. PeekJBAA, 41, 442 (1931)**
    (See note 4.)
    1933R. L. Waterfield*JBAA, 43, 240 (1933)
    (See note 4.)
    1935R. L. Waterfield JBAA, 45, 347 (1935)
    (See note 4.)
    1937R. L. Waterfield JBAA, 47, 351 (1937)**
    (See note 4.)
    1939R. L. Waterfield JBAA, 49, 378 (1939)**
    (See note 4.)
    1941R. L. Waterfield JBAA, 51, 350 (1941)**
    P. M. Ryves
    & A. F. O'D. AlexanderMBAA, 37, part 1 (1951)
    1943P. M. RyvesJBAA, 54, 182 (1944)**
    (See note 4.)
    1946P. M. RyvesJBAA, 56, 155 (1946)**
    (See note 4.)
    1948P. M. RyvesJBAA, 58, 239 (1948)**
    (See note 4.)
    1950P. M. RyvesJBAA, 60, 216 (1950)**
    (See note 4.)
    1952P. M. RyvesJBAA, 62, 253 (1952)**
    (See note 4.)
    JBAA, 64, 338 (1954)**
    (See note 4.)
    1956E. H. Collinson *JBAA, 67, 123=96124
    JBAA, 68, 142 (1958)
    1958E. H. CollinsonJBAA, 70, 252 (1960)
    1960E. H. CollinsonJBAA, 73, 23 (1963)
    1963E. H. CollinsonJBAA, 75, 171 (1965)
    1965E. H. CollinsonJBAA, 77, 202 (1967)
    (See note 5.)
    1967E. H. CollinsonJBAA, 79, 53 (1969)
    1969E. H. CollinsonJBAA, 81, 49 (1970)
    1971E. H. Collinson*JBAA, 82, 172 (1972)
    JBAA, 83, 283 (1973)
    1973E. H. CollinsonJBAA, 85, 336 (1975)
    1975E. H. CollinsonJBAA, 88, 504 (1978)
    1978E. H. CollinsonJBAA, 90, 560 (1980)
    1980R. J. McKimJBAA, 94, 197 (1984)
    1982R. J. McKim*Inner Planets Newsletter,
    Nos. 8, 9 (1983)
    *JBAA, 93, 175=96176 (1983)
    JBAA, 96, 36 (1985)
    1984R. J. McKim*Inner Planets Newsletter,
    Nos. 11, 12 (1984)
    *JBAA, 94, 271 (1984)
    JBAA, 97, 139 (1987)
    1986R. J. McKim*JBAA, 96, 256; 97, 2 (1986)
    JBAA, 97, 181, 191=96192 (1987)
    JBAA, 99, 215 (1989)
    1988R. J. McKim*JBAA, 98, 336=96337 (1988)
    JBAA, 99, 2=963, 52=9653, 115,
    154=96155 (1989)
    JBAA, 101, 264 (1991)
    1990R. J. McKim*JBAA, 101, 73 (1991)
    JBAA, 102, 248 (1992)
    1993R. J. McKim*JBAA, 102, 312=96313 (1992)
    JBAA, 103, 58=9659 (1993)
    JBAA, 105, 117 (1995)
    1995R. J. McKim*JBAA, 105, 157 (1995)
    1997R. J. McKim*JBAA, 107, 5, 61, 114=96115,
    175=96176, 231=96232 (1997);
    108, 243=96246, (1998)
    *Mars Section Circular Nos.
    1=9614 (1996=9697)
    1999R. J. McKim* Mars Section Circulars 
    1.  1922: Some observations by BAA observer P. M. Ryves appeared in the Mars
    Reports by Pickering.
    2. 1924: Steavenson's personal observations were published in the Greenwich
    Observations for 1924. Some observations by BAA observers appeared in the
    Mars Reports by Pickering. See also the various reports of the BAA Meeting
    3. 1926: Some observations by BAA observers appeared in the Mars Reports by
    Pickering. See also BAA Meeting discussions.
    4.  See also BAA Meeting discussions. Until ca. 1935, some observations by
    BAA members appeared in English Mechanic.
    5. 1965: from this year onward, some BAA observers also sent work for
    publication in The Astronomer magazine, but little Mars work has been
    published there since the early 1980s.
    An old drawing by E.M. Antoniadi
    Peter Hingley has published one of Antoniadi's coloured Mars drawings in the
    RAS magazine, Astronomy & Geophysics. This drawing is in the RAS archives
    (see the 1999 June issue, page 7, where, oddly, north is uppermost). I
    published a black and white version of the same drawing (dated 1909 September
    20) in my biographical study of Antoniadi, which Peter refers to. Antoniadi
    published some of his 1909 drawings in colour during his lifetime, but such
    reference sources are not readily available today.
    Pages from Pathfinder (and MGS!)
    In the same issue of the RAS magazine, page 6, the editor notes the
    availability of a special section  (576 pp) of the 1999 April 25 issue of 
    Journal of Geophysical Research devoted to the Pathfinder results. The
    principal scientific results include discoveries of:
    "* the spin pole and precession rate of Mars since Viking, 20 years ago;
    results require a central metallic core of radius between 1400 and 2200
    * evidence of warmer and wetter times in the past;
    * a dusty lower atmosphere where 'dust devils' are common;
    * ice clouds are common in the early morning, and morning near-surface
    temperatures change abruptly with time and height."
    On page 4, same source, the magazine's Editor briefly discusses the 'magnetic
    stripes' discovered by MGS on parts of the martian surface, and the possible
    implication of past tectonic activity by analogy with the stripes on Earth's
    ocean floors, caused by crustal spreading.
    BAA Exhibition Meeting
    UK members may wish to know that I will be displaying some of the Section's
    work at the BAA Exhibition Meeting later this month. This is the first time I
    have been able to attend in person since my term as BAA president (1993-95),
    so I am looking forward to meeting old and new friends.
    Reporting data to the Section
    I am always happy to receive CCD images by email. Any URGENT and important
    drawing can be scanned and sent as an image file, but I do not want to
    receive routine drawings by email, because the vast majority are sent to me
    as hard copies, and that is the form I like to compare (and archive) them in.
    I have to again write that I am spending a disproportionate amount of time
    downloading files sent to me over the Internet, then decoding, analysing and
    refiling them in the Section's records! Send mail to Cherry Tree Cottage, 16
    Upper Main Street, Upper Benefield, Peterborough PE8 5AN, Great Britain; home
    telephone 01832-205387; home email (Do not use the former
    email address for my place of work ( Urgent
    faxes can be sent to my place of work on 01832-274052.
    The next Circular
    Please report the June observations by July 10, so that the next circular can
    be issued by mid-July.
    Good observing!
    Richard McKim, Director, 1999 June 20th
    Back to Date Menu

  • March 1 - April 15, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 5
    This Circular summarises the period 1999 March 1- April 15. On Mar 1, Ls =
    104 deg., D = 10 arcsec., lat. of centre of disk = 15 deg. N, with the
    planet's declination at 13 deg. south. The planet will reach opposition on
    April 24 (Ls = 129 deg., D = 16 arcsec., lat. of centre of disk = 18 deg. N,
    decl. -12 deg.). The planet was becoming uncomfortably low for UK observers,
    but as can be seen, its declination will now be very slightly less southerly.
    The UK weather has been less than cooperative during opposition month, but
    nevertheless there have been a fair number of observers, including the usual
    contributions from overseas that are essential to maintain good longitudinal
    coverage. During the present apparition I have had observational data from
    the following individuals, and acknowledge it herewith if not already done so
    by letter or by email: Leo Aerts, Sally Beaumont, Nicolas Biver, Ed Crandall,
    P.Devadas, Mario Frassati, Martin Gaskell, David Gray, Peter Grego, Walter
    Haas, Alan Heath, Carlos Hernandez, Frank Melillo, Cliff Meredith, Masatsugu
    Minami /OAA, Patrick Moore, Don Parker, Damian Peach, Tom Richards, Richard
    Schmude, David Strange, Paolo Tanga, Gerard Teichert, Rowland Topping, Dan
    Troiani/ALPO, Johan Warell, Sam Whitby and Jonathan Wojack.
    More than one observer has supplied unreadable CCD image files: I do not
    always have the software to decode compressed files, and it would sometimes
    save time to mail a disc. I would also kindly point out to observers that I
    do not always have time to look for images on their personal Websites, much
    as I would like to; if you want your images discussed in these reports,
    kindly send them along in a readable format!
    I am sorry that Dr Ebisawa's health has not been very good, so that he has
    not been able to make his usual meticulous visual and polarimetric 
    observations so far. Is anyone doing polarimetric work this apparition?
    On Mars throughout March and April the N. polar cap remained small. A number
    of visual and CCD observations show haze around its S. perimeter. Despite
    this haze the outlying bright area of Olympia has been visible. Tanga saw it
    from Turin Observatory in fine seeing on April 18. White cloud activity
    remains quite high, but the Equatorial Cloud Band phenomenon (ECB) seemed
    much less conspicuous in April. The typical sites for white clouds have been
    active throughout the whole period, and a few observations will suffice to
    illustrate these locations and to describe some other features:
    McKim, April 13, 22-cm refl., 2318h UT, CML = 218 deg. Elysium on mid-disk
    whitish. Bright am cloud over Libya-Isidis (and Syrtis Major). Hellas a
    brighter spot within the light S. limb area. Cebrenia lightish on the CM,
    some haze S. of NPC, but cap edge sharp. Some pm cloud over Amazonis, but Nix
    Olympica would have rotated off the disk at an earlier hour. The Aetheria
    secular darkening remains extensive and dark, and extends somewhat to the SW
    as in the last few apparitions. Propontis (I) is dark, and the
    Phlegra/Styx-Trivium Charontis-Cerberus complex, though not dark, was easy to
    Meredith, April 14, 22-cm refl., 2355h UT, CML = 218 deg. CCD image much like
    McKim's visual drawing above. (Cliff's first really successful CCD work,
    well done to him.)
    Parker, March 7, 0.4-m refl., ca. 0735h UT, CM = 321 deg. Evening cloud dims
    Syrtis Major, extending across it from Libya to Aeria! The evening Hellas is
    bright. Morning cloud occupies Chryse and partly hides SW Mare Acidalium.
    Haze south of the NPC.
    Parker, March 12, ca. 0803h UT, CML = 282 deg. Hellas is very bright in white
    light. As Minami points out in the OAA's CMO, the brightness sometimes
    extends outside the contours of the basin: Gray found a similar phenomenon
    with Argyre in January.) Hellas was large and bright in green (VG9 filter)
    and blue (BG12), but was smaller and paler in red (RG610).
    Parker April 3. This CCD image series even shows a little structure inside
    the Solis Lacus (which remains large and dark since the mid-'80s). The
    feature Gallinaria Silva, a small dark spot that was seen to the W. of the
    Solis Lacus in the apparitions immediately before the present one, seems to
    have nearly disappeared. This is therefore perhaps a small change since 1997.
    There is really fine structure in the Tithonius Lacus between Melas Lacus and
    Noctis Lacus! Aurorae Sinus appears detailed, with little northward
    projections including Baetis/ Juventae Fons, etc. Mare Acidalium and Niliacus
    Lacus are shown in fine detail. Hyperboreus Lacus is a dark spot adjacent to
    the small NPC.
    Teichert, April 10, 28-cm SCT, 0056h UT, CML = 277 deg. Hellas bright on the
    CM. Nepenthes is invisible. Moeris Lacus forms a small protrusion on the E.
    side of Syrtis Major.
    I do not intend a more complete analysis here. UK members may wish to know
    that I will be showing some illustrations of the Section's work in my
    presentation at the BAA Northampton Meeting on Saturday April 24.
    Pic du Midi Website
    This is an excellent site (, and contains
    some medium to high resolution images of Mars  (1988-1999).
    LPL Mars Water Group
    Ann Sprague emailed with more details of her LPL Mars Water Group's work at
    Catalina: see Rik Hill's communication from the same group in the last
    Circular. Anne writes that they have been measuring water vapour in the
    martian atmosphere every two weeks since 1998 September. "We are measuring
    CO2 molecular absorption with the hopes of using radiative transfer to
    measure atmospheric dust... the depth of the water vapor absorption line in
    Mars' Northern latitudes is much deeper than we have seen it in previous
    Northern summers."
    February dust storm follow-up
    Last time's Circular detailed a Regional storm over the Mariner Valley, whose
    observation was mostly due to David Gray. Todd Clancy emailed on March 10 to
    report that this event (which had first been detected on February 21) had had
    no apparent effect upon the atmospheric temperature (as deduced from radio
    waveband work), but, interestingly: "the overall trend in temperatures over
    the past two months is 5-10 K warmer  than at this time in the previous Mars
    year." For those wishing to see David Gray's two sketches of the event, they
    may now do so thanks to Don Parker who scanned them and uploaded them to the
    Marwatch Website. Steve Lee emailed descriptions of the HST images of March 3
    (CML 256, 280 deg.): these revealed ECB, but the CML was too high for them to
    show the Valles Marineris area.
    Note that the results of Ann Sprague's spectroscopy and Todd Clancy's work
    seem to fit nicely together! It will be interesting to see if this relates to
    the regression rate for the NPC.
    Yet more dust over Valles Marineris!
    A further event occurred during the Director's absence on holiday abroad.
    Upon his return home on April 11, awaiting him was an email and observation
    by Carlos Hernandez, dated March 31 (22cm refl., CML = 53 deg.), which
    revealed an already mature dust storm in progress, in the form of a bright
    streak running E-W along (the S. edge of?) Valles Marineris. At first sight I
    thought it might just have been residual dust (see my comments upon Don
    Parker's March 3 CCD image in the last Circular), but Carlos had not noticed
    it earlier, and, moreover, it was too prominent, too well defined, and was
    bright through a W23A red filter. In his email Carlos mentioned that a CCD
    image by Antonio Cidadao taken 1h earlier had also shown the bright streak.
    Carlos observed again a few days later on April 2, finding that the area had
    returned essentially to normal. So when did it begin? Several days later,
    David Strange emailed a good CCD image taken on March 27 at 0100h UT under
    CML = 43  deg. This showed a bright area in Ophir which interrupted the
    Agathodaemon (also known as Coprates, part of  W. Valles Marineris: a
    classical 'canal' which runs between Aurorae Sinus (Planum) and Tithonius
    Lacus (Chasma)). This was most probably the initial cloud of the storm, and
    the event subsequently spread eastward along the canyon. Don Parker's CCD
    images of April 1 show the area, but in very bad seeing; his work on April 2,
    3 and 6 is high resolution, but apart from a possible faded appearance of
    Aurorae Sinus, the area seemed normal. Warell observed from Uppsala
    University Observatory, Sweden, with a 16-cm OG: on March 29, 30 and April 1
    (CML = 23-34 deg.) he found a large am cloud over Tharsis and Thaumasia,
    etc., to appear distinctly yellowish. Johan's seeing conditions were not good
    enough for him to see the dust actvity in the Valles Marineris, but the
    yellow tint could represent dust diffused from the minor storm then underway.
    Ditto April 5, under CML = 322 deg., when a yellow tint was evident in the
    Chryse-Xanthe am cloud. In any case, a short-lived event.
    Does anyone else have pertinent observations? If so, kindly let the Director
    know! Looking at the Pic du Midi website will reveal a March 24 image which
    does not show the storm, so we appear to have pinned it down quite well. The
    location of the 1984 June Regional storm fell in a similar location; in that
    case, dust also spread to the east over the same area, as well as dispersing
    generally over Mare Erythraeum. This storm was fully described in the
    writer's published 1984 BAA apparition report.
    The Director looked up the work of the group that are analysing solar radio
    occultation data from MGS to determine atmospheric temperatures. There is a
    section on the MGS homepage. Joe Twicken of that group kindly (and rapidly)
    responded to a query from the Director with the following email. " We have
    not processed the raw data that we do have for the dates that you mention. We
    do have a lot of data from the February period, but very little from the
    March period. MGS did not begin normal mapping operations until this month.
    Precise reconstructions of the spacecraft orbit are required to process our
    raw data, and the orbit reconstructions from JPL for the February and March
    periods were not sufficiently accurate for us to retrieve meaningful
    atmospheric profiles. Other members of our Team are in the process of
    reconstructing the orbits, and we will process the data when we can. I will
    let you know if we see anything interesting. You should be aware that the
    spacecraft occultations during the periods you mention occurred at very high
    northern and southern latitudes, so we will not have any atmospheric data
    from the vicinity of Valles Marineris."  Thus it seems that the only record
    of the March storm is again that of the groundbased observers. Keep up the
    good work, everybody! But for your observations, these two small but
    important events would have been completely missed!
    Mars as seen through the eyes of the Global Surveyor
    MGS has begun to image the planet from orbit again, after achieving final
    orbit about March 1. In the current (May) Sky & Telescope Jonathan McDowell's
    Mission Update column mentions a dramatic incident at Mission Control which
    nearly interfered with the attainment of the final orbit...
    Since the release of the Aerobraking Image Set, the MGS website has been
    posting full-disk and closeup images from March and April. These show how
    successfully the craft is behaving, and whet the appetite for more! Polar
    dune fields, craters, clouds, Valles Marineris (including a fine shot of E.
    Tithonium Chasma, image MOC2-109)... But telescopic observers will be most
    interested in two full-disk 'images', reconstructed from a sequence of nine
    strip-maps obtained on successive orbits. These were obtained in March during
    the calibration phase of the mission. The Director has emailed for a more
    precise date in case the images can support the discussion of the latest
    Valles Marineris dust storm. The colours will not be perfect as the Martian
    Orbiter Camera (MOC) makes red and blue images, and averages them to make 
    a 'green' image to combine with the others to make a colour composite. Another
    consequence of this process would seem to result in rather low albedo
    contrast compared with that telescopic observers can enjoy. (No matter, just
    try Adobe Photoshop or similar program on your PC, and you can make them look
    more like telescopic images - and put south at the top at the same time!!)
    MOC2-117 shows Syrtis Major central, partly covered by the bluish-white 'Syrtis 
    Cloud'. Iapigia shows the location of the large Huygens crater.
    Hellas is bright and looks mostly (but not entirely) frost-covered. The NPC
    shows fine rifts and the broad dark Chasma Boreale (Iaxartes). The fine
    albedo details around Utopia-Boreosyrtis-Propontis look to be very similar
    (if not identical) to 1997, as 1997 looked identical to 1995 in the HST
    MOC2-118 is an image of the Tharsis and Thaumasia regions. The morning clouds
    cover Olympus Mons, Alba Patera, Ascraeus Mons, but affect Pavonis and Arsia
    Mons less.
    The Mars Dust Storm Memoir
    At last I can report that everything is finished and checked, and that I will
    be taking the text and figures to the printer, University Printing Services,
    Cambridge (the printers of the BAA Journal), in the next couple of days. It
    is to be hoped that it can be published in the next few months. The printed
    text will occupy about 168 pages, equivalent to THREE 56-PAGE ISSUES of the
    Reporting data to the Section
    I am always happy to receive CCD images by email. Any URGENT and important
    drawing can be scanned and sent as an image file, but I do not want to
    receive routine drawings by email, because the vast majority are sent to me
    as hard copies, and that is the form I like to compare (and archive) them in.
    I have to write that I am spending an enormous amount of time downloading
    files sent to me over the Internet, then decoding, analysing and refiling
    them in the Section's records! Send mail to Cherry Tree Cottage, 16 Upper
    Main Street, Upper Benefield, Peterborough PE8 5AN, Great Britain; home
    telephone 01832-205387; home email (Do not use the former
    email address for my place of work ( Urgent
    faxes can be sent to my place of work on 01832-274052.
    The next Circular
    Please report observations April 16 to May 31 by June 7, so that the next
    Circular can be published in the second or third week of June.
    Good observing!
    Richard McKim, Director, 1999 April 23 (Opposition Day minus one!)
    Back to Date Menu

  • February 1-28, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 4
    This Circular summarises the period 1999 February 1-28 (but with an incursion
    into early March). On Feb 1, Ls = 91 deg., D = 7.9 arcsec., lat. of centre of
    disk = 18 deg. N, with the planet's declination at 10 deg. south, some 5
    degrees lower in the N. hemisphere skies than last month!
    At my suggestion Jim Bell included Circular No. 3 in the last Marswatch
    Electronic Newsletter, with a circulation of 1455 (only 1355 more than mine).
    More good news is that next month marks the start of the main mapping mission
    of Mars Global Surveyor. The craft has achieved its final, more circular
    orbit, and will hopefully take many hi-res images. On the MGS webpage there is
    now the 'Aerobraking Image Set' available for viewing and downloading.
    National Geographic has just published a new Mars book with many recent
    images. I have not seen it, but surely it will soon be out of date! (I am
    hoping somebody will send me a Review copy!) A general interest article by
    A.D.Andrews in the Irish Astronomical Journal was copied to me by Tony Kinder,
    BAA Librarian. Titled 'The Leviathans of Tharsis' its scope is self-evident,
    but I was surprised to find the BAA 1986 map, one drawing by myself, and
    several other drawings by past BAA observers used as illustrations (Reference:
    26 (1), 45-64 (1999)). John Rogers draws attention to several pieces in Nature
    for 1999 February 18 (397, 560, 584, 586, 589 and 592) dealing with volcanism
    on the early Mars, recent volcanism deduced from crater counts, dune-fields,
    etc., as revealed by the MGS spacecraft during the early phase of its mission.
    On Mars throughout February the N. polar cap appeared rather small, and at
    some longitudes the dark rim seemed hard to see, or was absent. Parker's CCD
    images sometimes showed some white haze just S. of the NPC, and this was the
    case in the most recent images of March 3 (CM = 5-12 deg.). White cloud
    activity presently remains high, and the Equatorial Cloud Band phenomenon
    (ECB) has been very conspicuous in the CCD images, especially in blue light.
    Elysium was brighter in the afternoon, and Hellas brightened considerably  in
    early February, being markedly lighter than in the previous month, sometimes
    with a brighter spot in its NW corner. The 'Syrtis Blue Cloud' has been imaged
    again by Parker. More observers are becoming active, and are sending in work:
    thanks to S.Beaumont, A.W.Heath, Dr T.J.Richards and Dr R.Topping  for recent
    Rik Hill emailed to say that his group at LPL were observing the planet every
    fortnight (primarily to monitor atmospheric water vapour) with the 61-in
    telescope at Catalina. He reports: "Our observations indicate the possibility
    of enhanced dust south during the period a week to either side of 1 Feb." The
    Director emailed early data about the Valles Marineris storm reported below,
    although this event occurred a little later in February, as will be seen. I
    have asked Rik for more details of his work.  
    Dust storm over Valles Marineris!
    Rather than report the mundane, this month's Circular is devoted to the story
    of a regional dust storm which was observed in the second half of February. On
    February 21 David Gray (42-cm Dall-Kirkham Cass., with x262-x415, Spennymoor,
    County Durham, Great Britain) observed considerable obscuration of the
    markings and kindly notifed me at once by telephone. I immediately issued an
    email alert to about 20 observers in Europe, the USA, Australia and Japan, and
    telephoned several UK observers who are not on email. The response was
    gratifying, although I have had no news from Japan as this issue goes to
    press. Although we may not have caught the precise start of this regional
    event, its decline and fall (as Gibbon might have written) was well followed.
    I recently emailed Todd Clancy to ask whether the dust has had any measurable
    effect upon martian atmospheric temperatures, as revealed through his radio
    waveband work. Selected details of the observations follow:
    Feb 19, 0700-0730 UT, CM = 101-108 deg, D.C.Parker, visual, 15-cm refl., from
    Chiefland, Florida: Don emailed this observation after hearing about the
    storm. He may have witnessed its start by noting a bright cloud on the
    terminator: "It was very bright in integrated and blue light, but not
    especially bright in red. On one occasion of excellent seeing, however, I
    thought it had a peculiar hook shape, reminiscent of dust". This must have
    been over Xanthe at the CML quoted, perhaps close to Aurorae Sinus. (I await
    sight of Don's sketch.)
    Feb 19, 1756 UT, CM = 261 deg, T.J.Richards (Victoria, W. Australia): A nice
    CCD image with his 18-cm OG, showing the Syrtis Major side of the planet
    completely normally and in fine detail.
    Feb 21, 0210-0300 UT, CM = 12-24 deg, D.Gray: Most of the SW (S. following)
    part of the disk was distinctly light, even in poor moments of seeing. A
    brighter, elongated core was seen, especially in red (W25). This core was like
    a 'V' on its side, with the apex occupying the N. part of Margaritifer Sinus,
    one fork running along or close to the Valles Marineris, and the other running
    off towards the SW limb, covering part of Mare Erythraeum. Margaritifer Sinus
    was quite invisible. Sinus Sabaeus was well-marked, but the 'Forked Bay' area
    (Sinus Meridiani) and the S. part of Mare Acidalium both seemed a little
    obscured too. A more diffuse brightness covered the equatorial deserts from
    the CM westward (Chryse, Xanthe, etc.), and this region was bordered on the E.
    by a dusky curving streak. Nothing could be seen of Aurorae Sinus to the west.
    Seeing was almost continually good throughout.
    Feb 21, 0600 UT, CM = 68 deg, Hernandez (USA): N. Margaritifer Sinus and Mare
    Erythraeum are faint. Agathodaemon (W. half of Valles Marineris, between
    Aurorae Sinus and Tithonius Lacus) is dark. Chryse-Xanthe bright in red light.
    To the west, Solis Lacus is dark, and that region appears normal. (I have not
    yet seen the drawing made by Carlos; it was most useful that he observed a few
    hours after Gray, so that his observation places limits on the W. side of the
    dust storm.)
    Feb 22, Gray: Very windy and with poor seeing. Mare Acidalium on the CM.
    Bright cloud is again seen from about the CM to the following limb.
    Feb 22, CM = 126-128 deg, F.J.Melillo (USA): Near-blank red light CCD images,
    but on a small scale, and at too high CML to catch the storm.
    Feb 23, 0520 UT, CM = 40 deg, Gray: In fine seeing he found the Aurorae Sinus
    area very faint (and it is drawn very ill-defined), but the Margaritifer Sinus
    and Mare Erythraeum regions have darkened again, and are as dark as M.
    Acidalium. Agathodaemon is dark, as is Solis Lacus. Chryse-Xanthe is light, as
    is the whole of the following part of the disk: Candor, Tharsis, Tempe. All
    this light cloud has rendered Nilokeras faint, and Ganges nearly invisible. By
    0600 UT the Chryse-Xanthe area was less bright. As ECB had been observed in
    these longitudes before the event, there was probably a mixture of white cloud
    and dust.
    Feb 23, CM = 119 deg, S.Whitby (USA): With a 15-cm refl. Chryse-Xanthe bright
    on the evening side, more so in red than in blue, but observer unable to see
    anything else due to small aperture.
    Feb 24, CM = 81-93 deg, Parker (USA), 41-cm refl., CCD work (and below):
    seeing evidently not very good, but Solis Lacus dark. Strong ECB right across
    the disk, including the evening Chryse-Xanthe. The Aurorae Sinus region is not
    well placed.
    Feb 26, CM = 15-25 deg, Gray: The S. features look much as on Feb 23 (Gray),
    with Aurorae Sinus still weak. Equatorial cloud present. I have not yet seen
    David’s drawing of this date.
    Feb 26, CM = 75 deg, Parker: Aurorae S. is present but not dark: seeing is not
    very good. ECB evident.
    Feb 26, T.Stryk (ALPO, observation passed on to me by Jim Bell): observer
    remarked upon the region of Candor-Tharsis, that was bright in red light.
    Certainly Candor is also light in Parker's February CCD images generally, but
    whether it was enhanced during the storm I have not yet decided.
    Feb 27, CM = 52-67 deg, Parker: As Parker, Feb 26.
    Feb 28, CM = 33-61 deg, Parker: seeing looks better than on 24, 26, 27.
    Aurorae Sinus looks normal in shape, but still perhaps less dark than usual,
    as it is definitely not as dark as the (now clearly normal) E-W dark band of
    the Mare Erythraeum. The ECB is incomplete at this CML, with some cloud in S.
    Chryse-Xanthe, then unconnected cloud over Ophir-Candor-Tharsis on the a.m.
    side. What is perhaps significant is that the images show the 'canal' known as
    Hydaspes visible as a halftone streak curving its way from the W. side of
    Margaritifer Sinus to somewhere about the SW side of Niliacus Lacus. This
    feature is rarely seen, though it was recorded as being dark during 1858-1871.
    Did it darken by surface excavation at the NE edge of the storm? I wrote the
    above description before I read Don's own notes: he independently noticed the
    Hydaspes, and drew attention to it.
    March 3, CM = 5-12 deg, Parker: good seeing. My impression of this CCD image
    is that some residual dust shows up very weakly as a thin E-W streak in red
    light just N. of Mare Erythraeum, and that there is a distinctly brighter
    cloud (dust) in red light just NE of Aurorae Sinus. Extensive but diffuse
    brightness is seen in Chryse-Xanthe (perhaps brightest in red light), and in
    Tharsis and Tempe (the latter regions were brightest in green and blue light).
    There is an ECB from the p. terminator to the f. limb. The albedo markings
    look very nearly normal to me on these images.
    In character and evolution the February storm was not very different from
    those of 1984 April (Ls = 132), 1990 October (Ls = 308) and 1997 June (Ls =
    139), described in past BAA Section Reports by the undersigned. If we accept
    the Feb 19 observation as marking the start, the storm was highly active and
    near maximum on the 21st, but was already dispersing by Feb 23. On Feb 28 and
    Mar 3 only traces of dust remained. 
    Thus the storm began near Ls = 99 deg., which is seasonally a bit early
    compared with former telescopic events which definitely began over Valles
    Marineris: my historical research shows that the earlier storms (1924-1990 and
    ?1879) occurred during the interval Ls = 132-357 deg., with most events near
    the extreme limits. On the other hand, events which began in neighbouring
    Chryse/Xanthe have occurred in the intervals Ls = 96-225 and 308-344 (from
    records between 1903 and 1992), and the 1999 February event thus falls nicely
    within the first interval. Anyone else out there with more observations of the
    longitudes in question? Steve Lee emailed me to say that his group were to
    have obtained time on the HST on March 3, under CM 300 deg., and their results
    will be interesting to compare with Parker's on the same date (see above). HST
    imaging is to be much less intensive than in 1997 this apparition, as noted in
    an earlier Circular: the role of the ground-based observer is again underlined
    by the our coverage of the dust event. (And who says it is always cloudy in
    Great Britain?)
    The next Circular
    As I may be out of the country in early April I will attempt to issue a report
    covering March 1-April 15 during the third or fourth week of April. Therefore
    please report up to April 15 by, say, April 22.
    Reporting data to the Section
    I am always happy to receive CCD images by email. Any URGENT and important
    drawing can be scanned and sent as an image file, but I do not want to receive
    routine drawings by email, because the vast majority are sent as hard copies,
    and that is the form I like to compare (and archive) them in. Send mail to
    Cherry Tree Cottage, 16 Upper Main Street, Upper Benefield, Peterborough PE8
    5AN, Great Britain; home telephone 01832-205387; home email (Do not use the former email address for my place of work
    ( Urgent faxes can be sent to my place of work
    on 01832-274052.
    Richard McKim, Director, 1999 March 7
    Back to Date Menu

  • December 16, 1998 - January 31, 1999

    British Astronomical Association
    Mars Section Circular 1998-99, No. 3
    This Circular summarises the period 1998 December 16 - 1999 January 31 (Ls =
    71 - 91 deg., D = 5.7- 7.8 arcsec., lat. of centre of disk 24 -18 deg. N). I
    have received CCD images from Don Parker, Frank Melillo and Damian Peach;
    David Gray remains the most prolific visual contributor. The weather in the UK
    has not been very cooperative, but observers have made the most of any fine
    weather. From Hawaii Nicolas Biver put his 26-cm reflector to good use on a
    few mornings. The OAA CMO 211 described Japanese work during December 16 to
    January 15.
    The next Circular will discuss observations done in 1999 February, and I
    intend to compile it by March 7. Therefore please send any relevant work in
    time for it to be included. Most of the Circulars from the last apparition
    (and Nos. 1 and 2 from 1998-99) are to be found on the Mars Section website.
    There is a new MarsWatch site, now sponsored by the Astronomical League
    ( There is an article about how to
    observe the current apparition in the latest copy of the ALPO Journal (1998
    I hope to say something about the current round of Mars-bound spacecraft,
    later, perhaps in the next Circular.
    N. polar region
    The cap remains bright and conspicuous, though the latitude of the S. edge has
    moved much further north. On January 11 for example, Warell found it to be
    "brilliant white". Parker's images (e.g., January 20, under CM = 66-69 deg.)
    also show the dark patch Hyperboreus Lacus at the edge of the cap. Though the
    tiny disk militates against really detailed study, Parker's CCD work indicated
    some detached outliers to the S. of the cap, and detail within the cap itself.
    Thus on December 25, CM = 310 deg., the cap had a well-defined brighter patch
    following the CM with indications of further structure around the centre of
    the cap. This bright spot seems to be a seasonal feature, and it was shown in
    Parker's red filtered images as well as in the overall composited colour
    The most famous (and largest) seasonal outlier is Olympia. Antoniadi found it
    began to be separated from the cap near Ls = 80 and that the outlier could be
    followed up to Ls = 195. It is important to try to establish these seasonal
    dates for every favourable apparition, as some authorities have considered
    them variable from martian year to year. Further, being in fixed topographic
    positions, they provide another means of judging the seasonal progress of the
    polar cap. Parker's images of January 9 (CM about 170 deg.) imperfectly
    resolved Olympia at Ls = 81 degrees. Further observations please!
    A new study of the NPC recession from Earth-based and HST data covering the
    years 1990 to 1997 has recently appeared in Icarus (136, 175-191 (1998)).
    Written by B.A.Cantor, M.J.Wolff, P.B.James and E.Higgs it advances evidence
    that the recession rate varied slightly during these four apparitions, the
    rate of recession being a bit slower in 1994-95. BAA NPC data from 1993 (and
    1980-82) have already been published (R.J.McKim, J. Brit. Astron. Assoc., 105,
    117-134 (1995)), and recent (unpublished) analyses of the Section's work for
    1995 and 1997 suggests very small interannual differences during 1993-97. It
    is clear that the HST images are a quantum advance upon previous Earth-based
    work, but being comparatively few in number it is still vital that as many
    accurate measures as possible are made by ground-based workers. Cantor et al.
    agree with the writer's opinion (expressed in the 1993 Section Report, op.
    cit.) that measures of the north cap's E-W diameter involve systematic errors
    (due to limb darkening or diurnal clouds) when the contour of the cap is not
    located entirely within the visible disk. BAA data have been analysed for the
    cap latitude on the CM (N-S direction): visual drawings, filar micrometer data
    and measures from photographs, when made by the same method have yielded
    comparable results. But comparisons of micrometric data measured in the E-W
    sense have not agreed exactly. Thus historical comparisons can present a
    problem if the method of measurement has not been stated in the literature. In
    the course of his research for the BAA Dust Storm project, among appropriately
    dusty archives in both the USA and Europe, the writer found a great deal of
    unpublished polar cap data. Another project...? Perhaps.
    Atmospheric activity
    No clear-cut evidence of  dust storm activity has been found so far, but white
    cloud activity has increased, and there have been numerous records of the
    Equatorial Cloud Band (ECB) effect. The martian orographic clouds over Olympus
    Mons (Nix Olympica) and the Tharsis volcanoes have been very clearly imaged
    and observed visually. Rather than giving an incomplete preliminary
    meteorological report here, some selective notes of the more interesting
    observations are given below. All of Parker's work is CCD; the others, visual.
    Parker, December 19: CM = 11-18 deg. Chryse-Xanthe is lightish, as is Tempe on
    the a.m. limb following M. Acidalium.   
    Parker, December 23: CM = 341-346 deg. Chryse-Xanthe is light on the morning
    side (especially in green and blue light).
    Gaskell, December 24: Argyre is bright and bluish on the evening side, and
    there is extensive morning cloud over Tharsis to Solis Lacus.
    Parker, December 25: CM = 310-318 deg. Hellas on the evening side looks only
    vaguely light. A thin ECB is seen across the disk.
    Parker, January 1: CM = 250-256 deg. Elysium is light on the evening side.
    Hellas is only very slightly white in the morning, and there is some morning
    cloud over Aeria following Syrtis Major. In blue light (BG12) the Syrtis is
    invisible and the white cloud in Aeria enlarged. In an email Parker reports
    having seen the "Syrtis Blue Cloud" visually on this date.
    Gray, January 7: CM = 122 deg. Nix Olympica, on the CM, is not especially
    light, but is seen to be surrounded by a dark area, especially on the N. side.
    (With a phase angle of 36 deg., the local martian time would be about 1.20
    pm.) Tharsis, on the evening side, contains extensive bright cloud. The S.
    limb was rather light, too.
    Parker, January 9: CM = 158 - 178 deg. Orographic clouds over the Tharsis
    region on the evening side, somewhat blurred by the seeing. Elysium is well
    onto the disk on the morning side and looks bright. (Allowing for phase it
    must be near local noon over Elysium.) These bright patches are imaged
    especially clearly in blue light.
    Gray, January 10: CM =108-113 deg. Light S. limb. Tempe lightish on the p.m.
    side. Alba is light, crossing the CM. Nix Olympica on the a.m. side is also
    rather light
    Warell, January 11: Argyre light on the evening side and extended haze over
    Memnonia on the morning side.
    Parker, January 15: CM = 107-128 deg. The Equatorial Cloud Band effect is in
    evidence both in the blue light images and in the composited colour images. A
    bright equatorial cloud on the evening side thins out towards the west, and
    runs discontinuously across the disk where it meets a large bright cloud on
    the morning limb. The last images show a discrete Nix Olympica very bright
    approaching the CM (early  afternoon, local martian time). Morning cloud also
    completely surrounds Propontis I, a phenomenon noticed in 1997, 95 and 93 (and
    illustrated in the 1993 final Section Report). Cebrenia is also hazy.
    Gray, January 16: CM = 63 deg. The region just S. of Aurorae Sinus looks
    unusually pale as if affected by haze, but observing conditions are not
    perfect. On the evening side Chryse-Xanthe is a light region.
    Parker, January 18: CM = 87-101 deg. ECB and Nix Olympica again very evident
    (blue, green light and in composited colour CCD frames). The evening cloud is
    over Xanthe and Candor-Ophir.
    Parker, January 20: CM = 66-69 deg. Candor-Ophir is again light on the CM.
    Gray, January 21: CM = 355 deg. The S. limb, including Noachis, is very
    bright, the brightness extending to encompass the small part of Argyre that is
    visible on the a.m. side. On the morning side this cloud extends north over
    part of M. Erythraeum. Chryse-Xanthe also bright on the morning side.
    Gray, January 22: CM = 353-356 deg. Much as the 21st, but filter work shows
    that the a.m. limb part of the S. limb brightness is most conspicuous in blue
    and green light. (On both mornings this bright patch rapidly faded with time.)
    Surface features
    Propontis remains a conspicuous dark spot. Solis Lacus is still large and dark
    to Parker, Gray and Biver, as it has been since the mid-80's. It is elongated
    E-W. No internal details have been resolved yet. No trace has been found of
    the Phasis development to the W. side of Solis Lacus, which is in line with
    the gradual fade notice in the last few apparitions. As in 1997 the Cerberus
    region is not prominent, but it showed up faintly nonetheless in Parker's CCD
    images, as well as in Gray's drawings. Gaskell reports having picked up
    internal details in M. Acidalium.
     Erratum in Circular No. 2
    Apologies to David Gray for wrongly quoting the date of his Libya observation
    as December 23: it should of course have read November 23.
    Reporting data to the Section
    Send mail to Cherry Tree Cottage, 16 Upper Main Street, Upper Benefield,
    Peterborough PE8 5AN, Great Britain; home telephone 01832-205387; home email (Do not use the former email address for my place of work
    (which was You can also send any really
    urgent fax to my place of work on 01832-274052.
    Richard McKim, Director, 1999 February 7
    Back to Date Menu

  • November 16 - December 15, 1998

    British Astronomical Association
    Mars Section Circular 1998-99, No. 2
    Mars remains distant, so that many Section members have yet to begin work.
    This Circular summarises the period 1998 November 16 - December 15 (Ls = 58-70
    deg., D = 4.9 - 5.6 arcsec., lat. of centre of disk 25 - 24 deg. N), though
    some observations a little later and earlier have been added for comparison.
    Since publishing Circular No. 1 I have received two more of the OAA's
    bulletins (Nos.  209, 210) which cover the periods Oct 16-Nov 15 and Nov
    16-Dec 15 respectively. I have received nice CCD images from Don Parker and
    Frank Melillo; David Gray remains the most prolific visual contributor. Jim
    Bell emailed that HST coverage is unlikely to be extensive in 1999, which
    makes our efforts all the more worthwhile.
    Please note that all the following data have been obtained on a disk below 6
    arcseconds diameter: congratulations to all concerned!
    The next Circular will cover the period 1998 December 16 to 1999 January 31,
    and I intend to compile it by February 15. Therefore please send any relevant
    work to cover that period in time for it to be included. I have sent email or
    paper copies of Circulars 1 and 2 to all active Section members from 1997, and
    to others who might find it of interest. Inactive Section members may not
    receive further copies, please note!
    Most of the Circulars from the last apparition are to be found on the Mars
    Section website (see
    N. polar region
    The cap remains bright and conspicuous (with dark surroundings) though
    somewhat reduced in size. Selected measures indicate normal recession. During
    the period reviewed no internal details were reported in the cap.
    Atmospheric activity
    No dust storm activity has been reported, but there is some white cloud
    activity, reported in no special order below:
    Hellas: Whitish or slightly so at the morning limb, dull thereafter. Patrick
    Moore (Nov 17, CML 256-271 deg.) drew it fairly dull. Combined data show that
    it began to brighten after CML 280 to 300 deg., becoming very bright by
    martian evening (CML about 330 deg.). Gray on Nov 10, just before the period
    reviewed, found Hellas very bright at the evening terminator under CML 339
    deg., but it had gone off the visible disk by 345 deg.
    Chryse-Xanthe: Whitish to the OAA observers from about CML 50 deg. in the
    afternoon. Also seen light at the a.m. limb, but no brighter than other
    equatorial deserts at local noon.
    Libya: The OAA recorded "morning mist following Libya" under CML 265 deg. on
    Dec 9. Gray must have had a similar experience on Dec 23 when he found the
    Syrtis Major apparently slightly veiled when rising, under CML 233 deg. It was
    not seen to be light near the CM.
    Elysium: Light at the evening terminator, the a.m. terminator and lightish in
    the afternoon, but never really bright.
    Tharsis; Nix Olympica; Alba: On Dec 2 under CML 149 deg. Gray sketched a mass
    of extensive bright cloud over the evening (p.) terminator, from which Nix
    Olympica (the orographic cloud over the slopes of Olympus Mons) was but
    imperfectly resolved. Alba was light but not easy to the same observer at the
    terminator on the same date.
    Aeria: Some indications of both morning and evening cloud.
    Tempe: No reports of cloud activity here as yet.
    Noachis: Masatsugu Minami, Nov 25, 28, found it whitish on the evening
    terminator (20-cm OG).
    S. polar hood: A constant feature, but variable both diurnally and with
    longitude. Thus: Minami and Takashi Nakajima (OAA), Nov 23, S. limb hazy and
    light, especially on the morning side (CML about 50 deg.); Gray Nov 6 (CML 27
    deg.) p. side of hood brighter than the following in W58 green.
    Dark markings
    The following comments by Martin Gaskell  (20-cm refl., Dec 8, CML = 175 deg.)
    should encourage other Section members to start their observations: "The
    northern maria around the NPC (Scandia-Panchaia) were the darkest features
    visible. The diffuse dark markings in the Diacria-Propontis-Phlegra region
    were surprisingly dark in white light given that the disk was only 5.4
    arcseconds across." No changes in the markings from 1997 have yet been
    detected, but increasingly fine surface details are being recognised. Thus
    David Gray did well to make out the little N-S elongated "oasis" of Nodus
    Alcyonius Np. the Syrtis Major. On Nov 23 Minami, with Nakajima, was even able
    to detect colourations with a 20-cm OG. M.Acidalium was slightly dark brownish
    and the Aurorae Sinus region dark bluish.
    On this last point of colour, the Director wonders if the difference in colour
    between such markings at aphelic apparitions can be ascribed to the presence
    of the bluish-white equatorial cloud bands? Such bands would tend to make the
    Aurorae Sinus, Syrtis Major, etc., more bluish than far northern areas such as
    Utopia and Mare Acidalium, even though the bands are rarely visible through
    direct observation near the CM with small telescopes. If this explanation is
    correct (rather than there being real differences in the hues of the dark
    markings themselves), then we can deduce that the ECB were present in many
    past apparitions even if they were not reported as such (e.g., 1935, 1952,
    and through to the present time). It will be easy to search the literature for
    earlier examples, though these are the earliest I can think of offhand where
    there were significant tonal differences in the manner described.
    From the bookshelf
    "Patrick Moore on Mars" is the title of a popular new Mars book by Patrick,
    his first for two decades. It is published by Cassell (1998), and it is
    recommended to members as an excellent guide to the Red Planet. Patrick is
    unique in having contributed observations to the Mars Section at every
    apparition from 1948 to the present.
    Iakovos Stellas writes from Athens that he has completed the draft of a
    translation of E.M.Antoniadi's book, 'The Planet Mars' from English into
    Greek. He hopes to have discussions with publishers about the chance of
    printing an edition in Antoniadi's native language, which would be very nice.
    In the 1970s Patrick Moore translated the original French edition of 1930 into
    I am often asked if this English edition is still available, and always have
    to say that it has been out of print for some years. If any member comes
    across secondhand editions of this, or any other classic Mars books, and does
    not want them for him or herself, please let me know as I may be able to match
    people with books. For myself I would like to find the French edition of
    Schroeter's Mars book: I have it in German but cannot easily read it! I would
    also be interested in getting copies of the Annals of the Lowell Observatory,
    the formal reports on Mars by Lowell and his assistants covering the years
    1894 to 1903 (volumes 1-3).
    Reporting data to the Section
    Send mail to Cherry Tree Cottage, 16 Upper Main Street, Upper Benefield,
    Peterborough PE8 5AN, Great Britain; home telephone 01832-205387; home email (Do not use the former email address for my place of work
    Richard McKim, Director, 1999 January 7
    Back to Date Menu

  • November, 1998

    British Astronomical Association
    Mars Section Circular 1998-99, No. 1
    Mars is still very far from opposition, but the writer knows of observations
    as early as August 19. Six observers have reported their work, and this
    Circular describes some details seen from then until November 15 (Ls = 7-57
    deg., D =  3.8-4.9 arcsec). Some notes about what to look for during the
    present apparition were published in the BAA Journal, 108 (5), 243-245 (1998).
    Although the planet is steadily drawing closer, its N. declination is
    decreasing, and will become S. of the celestial equator in early December.
    North polar region
    With these early observations, on occasion no dark markings can be seen on the
    tiny disk, due to lack of resolution rather than dust storm activity. Even
    then, sketches that just portray the NPC accurately will be useful. Drawings
    may be made every 15 or 20 minutes. Remember to estimate the cap in tenths of
    the planet's diameter when transfering the mental impression to a Section
    report form.
    Observations did not begin early enough this year to document the transition
    from polar hood to cap. Sketches do show the decline in size of the NPC,
    though no fine details could be expected. A dark collar was seen by Nicolas
    Biver on September 20, 26, by Richard Schmude on September 27, by David Gray
    in October and by Mario Frassati on October 28. Drawings by Martin Gaskell
    during October 12-13 (Ls = 42-43 deg.) place the NPC S. edge at latitude= 70-72
    deg., and two by Gray on October 31 (Ls = 50 deg.) gave 74-75 deg. These
    results are very close to the BAA data for the earlier apparitions of the
    1990s (and 80s). More measures please!
    Atmospheric activity  
    Elysium: Gray reported slight whiteness here with the region near the CM,
    October 18, 19, and more so with the region on the morning side, October 22,
    23, whilst Biver's sketch of September 26 shows it light at the morning limb.
    (As Gray remarks, Elysium is sometimes detected not by its intrinsic
    brightness, but by the duskiness of its surroundings. Would observers
    therefore be explicit in their descriptions, please!) 
    Nix Olympica: detected as a light spot by Gray on the afternoon side on 
    October 23.
    Tharsis: On October 30 and 31 Gray reported a striking, large bright tongue
    of cloud, visible in white light and in W15 yellow, stretching from W.
    Tithonius Lacus (the latter feature, a dusky triangle, was near the CM, at CM
    long. 73 to 80 deg.), broadening towards the morning limb. Terrestrial cloud
    prevented a view in red or blue light. This seems to have been white morning
    cloud over Tharsis. The Director recalls a roughly similar view in February
    1995, at a very slightly later seasonal date, so it may be a seasonal type of
    cloud. There is no real evidence for it having been a dust storm.
    Chryse-Xanthe: bright on the evening terminator.
    Hellas: Under CML 254 deg. on September 20, Biver (10-inch refl.) did not draw
    it light. More data are needed for this region of the planet.
    The October work by Frassati and Gray reveals S. limb haze at all longitudes,
    sometimes very striking. A report by the OAA (Japan), October 2-9, confirms
    Dark markings
    These seem normal, like 1995 and 97. Using his 14-inch Dall-Kirkham Cass.,
    Gray has already made detailed sketches showing such small details as Idaeus
    and Achilles Fons on the Nilokeras streak. Solis Lacus remains large, as in
    all the apparitions from 1984 through 1997. The Propontis area was dark (at
    lo-res), as were the S. maria, Syrtis Major, Mare Adidalium, etc. The SE dark
    border to Elysium (Trivium Charontis-Cerberus) remains invisible or virtually
    Reporting data to the Section
    Please note that since the last apparition I have moved house, and am now
    living at this address: Cherry Tree Cottage, 16 Upper Main Street, Upper
    Benefield, Peterborough PE8 5AN; home telephone 01832-205387; office fax and
    answering machine 01832-274052; home email (Do not use the
    former email number for my place of work (
    Richard McKim, Director, 1998 November 20
    Back to Date Menu

  • June 1-15, 1997

    From Tue Jun 24 09:15:35 1997
    Mars, 1996-97: British Astronomical Association:
    Twelfth Report on observations 1997 June 1-15
    D: 9".0 to 8".2, Ls: 126 to 133 deg. UK weather and seeing conditions 
    remained fairly good, but several observers have ceased observing on 
    account of the diminutive disk. No changes in surface features have been 
    noticed. The summer NPC remains static and clearly defined. There has been 
    no indication of atmospheric dust activity. Selected observations are set 
    out chronologically; this report will be very incomplete in longitudinal 
    coverage but is released now on account of its topicality.
    Selected observations
    June 1 Meredith CML 312 deg: Hellas bright on p.m. side.
    June 4 Teichert CML 275 deg: Hellas and (p.m.) Elysium light. Observer 
    found Mare Hadriacum very dark.
    June 4 McKim CML 287-292 deg: Hellas bright. Syrtis Major is fainter than 
    the very dark M.Tyrrhenum. Hellas and (p.m.) Elysium bright.
    June 7 Gaskell CML 353 deg: Evening cloud over Libya. A band (of light 
    evening cloud?) the width of Hellas ran northwards from Hellas over 
    Iapigia towards Deltoton; it was of similar brightness to Deucalionis 
    June 8 Meredith CML 247 deg: normal albedo features.
    June 14 Schmude CML 263-272 deg: Syrtis Major weak (51-cm refl., x570); 
    suggests light a.m. haze, similar to diurnal effects seen in May. Also NPR 
    "dull white", and clouds at Np limb and Nf terminator.
    Richard McKim, Director
    1997 June 24th
    fax and answerphone 01832-274052;  home telephone 01832-274553
    email address
    To email recipients ONLY:
    I will not have the use of this email terminal except on rare occasions 
    during the School summer holidays, June 27 to August 29, approx., although 
    it may be possible to SEND one more email circular in early July. 
    Therefore please DO NOT SEND ME EMAIL during this period as it tends to 
    build up and cause the whole system to crash as it is shared by some 100 
    other users (in which case your message will be lost). But you can phone, 
    write or fax me. If you have not yet done so, please mail me hardcopies of 
    your observations (visual) a.s.a.p., together with any overall impressions 
    you may have of the apparition (which may be quotable in any later 
    report!). As this is more or less the end of the apparition, let me thank 
    you for your communications, and let us all hope that the NASA Mars probes 
    will be really successful. Watch the press this summer!
    Back to Date Menu

  • May 1-31, 1997

    From Mon Jun  2 10:58:32 1997
    Mars 1996-97: British Astronomical Association
    Eleventh Report on observations 1997 May 1-31
    Between May 1 and May 31, Ls increased from 111 to 126 deg., whilst the
    apparent diameter shrank from 11.5 to 9.0. Mars Pathfinder is still
    functioning well, and camera tests have been carried out. Larger
    meteorological and albedo features should remain observable given good seeing.
    New contributors included John Rogers (UK), Frank Melillo (USA) and Sam Whitby
    (USA). A Mars Telescopic Workshop (the second of its kind) is planned for
    October 2-3 in the Tucson mountain foothills, in order to define the state of 
    the martian atmosphere and surface just prior to the Pathfinder landing, and
    to compare the atmospheric activity in 1997 with recent apparitions. The
    Director has details for anyone interested in attending.
    More HST images
    The HST images described in issue no. 10 will feature in the August number of
    the Journal. Further HST images were acquired on March 20 but not released
    until May 20. One with CM long. 94 deg. (not reproduced here) shows Acidalium-
    Hyperboreus, several volcanic calderas, the complex Valles Marineris area and
    Solis Lacus. The Solis Lacus is still conspicuous but it is clear that the
    north-western (e.g., Nf.) part has faded, becoming overlaid with dust. The
    Phasis area has also faded out. Thus the whole region has returned to
    something more like its classical appearance, in contrast to the long sequence
    of changes from 1973 to the present. Greatly foreshortened this year, it has
    only been well-resolved in the HST images. A blue-light image (same CML) shows
    Tempe-Arcadia dark, confirming the telescopic impression of a rather strong
    reddish colour thereabouts. There was no polar haze. Next HST images are due
    on June 4 , and June 26-29.
    Back to the BAA observations covering May 1-31:
    North polar region
    The NPC summer remnant appears static; Hyperboreus Lacus was still easy to see
    at the close of the month. Olympia was still reported by the OAA (Japan) in
    early May. There was still no real sign of polar haze.
    Surface features
    Alan Heath's April drawings showed the Lunae Lacus large and diffuse; the
    Director had described it as conspicuous in a previous Circular, meaning large
    rather than dark. Several observers with relatively small apertures have seen
    the martian volcanoes as albedo features: they are also shown on the newly
    released Hubble image described above. For instance, Michael Hendrie on May 14
    saw Ascraeus Mons as a diffuse dusky smudge (15-cm OG, x330), as did several
    others. Cave on May 9 saw Nodus Alcyonius tapering to the south.
    Dust storms (yellow clouds)
    Nothing positive to report again.
    White clouds
    Throughout May, the Tharsis and Nix Olympica orographic clouds remained
    visible.  However, the preceeding limb no longer corresponds with the sunset
    terminator, and so (since April) the most favourable conditions for viewing
    the clouds under evening illumination have passed. Elysium appeared lightish
    near the disk centre and brighter at the limb or terminator. Some observers
    were lucky enough to see the small Elysium Montes cloud (e.g., Arthur Bowyer
    (30-cm refl.) on May 1, under CML = 242 deg.). Hellas remained bright
    throughout the martian day. Eridania, Ausonia and Argyre were also light.
    Libya-Isidis-Aeria and Chryse-Xanthe exhibited diurnal cloud activity, as did
    Tempe. The Libya-Isidis-Aeria cloud caused Syrtis Major to appear faint in
    whole or in part at the limb or terminator during May (and April).
    Richard McKim, Director
    1997 June 2nd
    fax and answerphone  01832-274052;  home telephone  01832-274553
    email address:
    Back to Date Menu

  • April 16-30, 1997

    From Sat May 10 07:07:17 1997
    Mars, 1996-97: British Astronomical Association:
    Tenth Report on observations 1997 April 16-30
    D:12".9 to 11".5, Ls: 105 to 111 deg. UK weather and seeing conditions 
    were a little less satisfactory than in the first half of the month, but 
    many observations came to hand. Vanessa Cave (USA), David Graham (UK), 
    Terry Platt (UK) and Antoine Van de Jeugt (Belgium) sent in their first 
    contributions of the apparition. Congratulations to Section member Dr 
    Patrick Moore on the 40th Anniversary of his 'Sky at Night' TV programme. 
    Earlier still, fifty years ago, at the 1947-48 apparition, Patrick made 
    his first contributions to the Mars Section, then directed by P.M.Ryves. 
    And he has sent in observations at every apparition since! Meanwhile, 
    NASA's Mars Pathfinder is still on course for a July 4 landing.
    Special comments upon the new HST images
    As recommended in a recent Circular the Director has studied the three 
    'colour' WFPC images released onto the Internet. All were taken on March 
    10, and released on March 20. There are other images too, filter versions, 
    but I will just discuss the colour set here, all of which have incredible, 
    diffraction-limited resolution (one pixel =3D 22 km on Mars!). Each colour 
    image combines blue (433 nm), green (544 nm) and red (763 nm) filter 
    images. The accompanying Press Release from the Space Telescope Institute 
    states that a preliminary analysis reveals some dust as well as water ice 
    crystal clouds over Terra Tyrrhena [Mare Tyrrhenum], Noachis Terra 
    [Noachis] and Hellas, as well as Vastitas Borealis. However, inspection of 
    the colour images shows little evidence of airborne dust.
    (A) CML =3D 160 deg. Olympus Mons is just E. of the CM, its caldera marked 
    by thin white clouds and the usual orographic cloud streaming over its 
    western slopes in a NW direction. Remarkable detail is seen in the evening 
    Tharsis orographic clouds which cover a good part of the E. limb. Euxinus 
    Lacus is very small on the CM. NPC outliers are seen in several places. To 
    the far south, Caralis Fons is clearly seen poleward of Mare Sirenum; the 
    NW end of the latter Mare remains obscure (since 1986, now).
    (B) CML =3D 210 deg. Elysium straddles the CM. The extraordinary pallor of 
    Trivium Charontis and Cerberus (I) is noticeable at once. Has the region 
    faded even further than in 1995? Trivium Charontis comprises a few tiny, 
    complex spots on my monitor screen, whilst Cerberus is invisible apart 
    from a tiny dark spot. Many observers have missed these features 
    completely this apparition (and last). Interesting that Elysium does not 
    appear on 19th Century sketches before the 1830s and 40s, when observers 
    such as Galle, Beer and Maedler drew it. Neither Herschel nor Schroeter, 
    nor any of their predecessors ever unambiguously figured it. It seems that 
    the area is now a site for dust deposition, and is enjoying a period of 
    obscurity! Had Cerberus-Trivium Charontis ever previously been as dark and 
    as intense as it was in the first decade of the present century, it would 
    have surely been recorded even in the 1700s. Thus perhaps the desposition 
    of dust there marks a return to the circulatory regimes that existed then, 
    when no evidence was found for large dust storms. On this HST image, the 
    other points of interest are the dark, comma-shaped Propontis I, looking 
    as it did in 1993-95, and the widespread shading between the lightish 
    Elysium and Propontis I, which is all that remains of Phlegra-Styx, the 
    classical E. border of Elysium. Note also the bright orographic cloud over 
    Elysium Montes near the CM, and the irregularities in Mare Cimmerium that 
    closely resemble the spoch 1988-95. Olympia is foreshortened near the CM, 
    and the polar ices are highly irregular.
    (C) CML =3D 305 deg., with the following edge of Syrtis Major central. 
    Hellas is bright, bluish-white, presumably frosted over, but also shows a 
    dusky E-W streak dividing the equally bright N. and S. halves. The detail 
    in the Syrtis includes the Huygens crater complex, and intricate 
    irregularities on all sides. Moeris Lacus seems unchanged since 1990. 
    Further north, the Nodus Alcyonius is a dark, elongated streak, but 
    contrary to the impression I reported from contemporary CCD images in a 
    recent Mars Section Circular, it is not connected to Casius/Utopia. 
    Nilosyrtis is a faint chain of small irregular spots, Boreosyrtis is 
    complex and remarkably like its aspect in 1990-95 (and in the USGS 
    albedo-topographic charts), whilst Nepenthes remains absolutely invisible. 
    The E. end of Sinus Sabaeus is pale, but reaches Iapigia. Edom crater is 
    visible, but not light on the morning side, while bright white evening 
    cloud covers Elysium. Aethiopis-Isidis shows very thin diffuse white cloud 
    seeming to merge with the limb haze on the E. side. The Deuteronilus seems 
    less well-marked than it appears in the ground-based visual and CCD work. 
    The NPC dark collar is some way south of the summer residual frost; this 
    may well have some bearing upon past ground-based measures of the summer 
    cap. The NPC summer remnant is complex, with the broad Chasma Boreale 
    cutting largely across the cap from the longitude of Mare Acidalium. 
    Olympia appears as a pale, irregular cap outlier, rather reduced in size.
    Back to the latest April 16-30 observations:
    North polar region
    The NPC summer remnant looks static now. Olympia was seen by Cave on April 
    16, when it was drawn rather small by him. Both Cave and Teichert on April 
    30 and 13-17 respectively saw a tiny white remnant near long. 10 or 20 
    deg. (March drawings just to hand from Niechoy also show some NPC 
    outliers, and both he and Graham found Ortygia rather bright on March 7 
    and 10, respectively.) Some observers report seeing the NPC surrounded by 
    a lightish region.
    Surface features
    Gaskell confirmed the Director's view of the apparently more conspicuous 
    Lunae Lacus (Circular No. 9). A pity the region has not been imaged by the 
    HST recently. Gaskell also commented upon the rich red colours visible in 
    the Arcadia region when observing with a friend's 51-cm reflector. Cave 
    continued to see Juventae Fons as very tiny and dark in excellent seeing. 
    Tanga on April 13 (42-cm OG, Turin observatory) was fortunate to see 
    "three tiny (but incredibly dark) dots corresponding to Ascraeus, Pavonis 
    and Arsia [Mons] (the last one on the [following] limb)." This calls to 
    mind one of the 1995 HST images where one of the summits of the volcanoes 
    poked through morning haze. The Director was lucky to see a similar 
    instance of this phenomenon in the 1995 apparition, but he did not catch 
    it in 1997.
    Dust storms (yellow clouds)
    Nothing positive to report.
    White clouds
    (An incomplete report!) The Tharsis and Nix Olympica orographic clouds 
    remained visible. The ALPO (Martian Chronicle, 1997 April edition) found 
    the Olympus Mons orographic cloud less prominent, only visible through the 
    W47 filter (blue-violet light). Southern limb haze was noticeable. Hellas 
    has been bright throughout the martian day: frosted floor now? Patrick 
    Moore, April 24, found Hellas as bright as he had ever seen it, and 
    brighter than the NPC. Teichert also found Hellas brighter than the NPC in 
    green, blue and red light. On April 29 the Director followed Hellas as it 
    appeared on the morning side. The S. limb was whitish under CML =3D 252 
    deg., as observations began; under CML 268 deg. Hellas was differentiated 
    from the general S. limb whiteness as a very bright patch. Eridania, 
    Ausonia and Argyre were light. Knott on April 20 drew Edom lightish in 
    blue (but not in white) light when somewhat W. of the CM. Elysium and 
    Tempe appeared lightish near the disk centre and brighter at the limb or 
    terminator. Libya-Isidis and Chryse-Xanthe are similar. No reports of the 
    'Blue Clearing' have been received, all W47 filter observations being 
    Richard McKim, Director
    1997 May 10th
    fax and answerphone 01832-274052; home telephone 01832-274553
    email address 
    Back to Date Menu

  • April 1-15, 1997

    From Thu Apr 24 12:46:22 1997
    Mars, 1996-97: British Astronomical Association:
    Ninth Report on observations 1997 April 1-15
    D: 13".9 to 12".9, Ls: 98 to 105 deg. UK weather and seeing conditions
    remained good.
    North polar region
    Again, no N. polar haze was evident in white ight. The NPC seemed to have
    reached its minimum size, but measurements will be needed to confirm this. 
    Hyperboreus Lacus was still conspicuous, and Olympia showed up on Dijon's 
    CCD work and to Shirreff (Apr 7) visually, on the morning side.
    Surface features
    Much fine structure was again seen. Observers paid attention to the fine 
    detail around Mare Acidalium, e.g., Hendrie on Apr 12 (15-cm OG) 
    accurately portrayed Acidalium's dark NW tail, Tanais, together with the 
    dusky Baltia. On Apr 15 the Director found Lunae Lacus rather large, and 
    apparently darker than before: he felt the region to be a little different 
    to its earlier appearance visually and upon the HST images. Observations, 
    please! In 1982 Lunae Lacus and Uranius darkened at the time of a dust storm 
    in Tempe-Arcadia.
    Dust storms (yellow clouds)
    There is nothing positive to report, but see the note on Lunae L. above.
    Dr Ebisawa (49-cm refl., Tokyo, Japan) has sent details of his work thus 
    far. Of special interest, on 1996 September 18, CML = 154 deg., Ebisawa 
    sketched a small southward inflexion in the NPC's contour; he notes that 
    this corresponds to the place of the dust storm imaged by the HST (see 
    earlier Circulars).
    White clouds
    Dijon's images (reproduced in the paper edition of this Circular) were 
    among the many received that showed the complex spotty pattern of evening 
    white clouds over Tharsis-Amazonis-Arcadia. Nix Olympia exhibited white 
    morning cloud, became less easy to see by local noon, then gradually 
    brightened towards evening. Several observers including the Director drew 
    attention to the large white morning cloud over Tharsis and E. Memnonia - 
    E. Amazonis, visible when Mare Acidalium was on or somewhat p. the CM. 
    S.Moore (22-cm refl.) on April 15 reported a small bright white cloud in 
    S. Tempe (seen in blue, invisible in red light), but the Director 
    contemporaneously saw only a general lightness in Tempe. The region showed 
    bright a.m. and p.m. clouds but was less conspicuous about mid-disk. 
    Elysium was bright on the morning terminator, Cebrenia being included or 
    brightening separately. Near the CM and in the afternoon, no more than a 
    small light cloud was seen over Elysium Mons, or a slight lightness over 
    Elysium generally. In the evening Elysium was wholly or partly brightened 
    by white cloud. Siegel on Apr 6, under CML = 100 deg., reported that an 
    equatorial cloud band was faintly visible in W47 and 80A, and very faintly 
    visible in W58 and integrated light. Other observations of the phenomenon 
    were reported by Troiani. Some observations of the 'Blue Clearing' were 
    again made.
    Richard McKim, Director
    1997 April 25th
    fax and answerphone  01832-274052;   home telephone 01832-274553
    email address
    Back to Date Menu

  • March 16-31, 1997

    From Wed Apr 23 10:46:17 1997
    Mars,1996-97: British Astronomical Association:
    Eighth Report on observations 1997 March 16-31
    The writer is very sorry to have to report the death of Dr Leonard Martin 
    in early April. Leonard made some outstanding analyses of the great dust 
    storms of the 1970s in a long professional career at the Lowell Observatory. 
    He had retired only recently. The Director met him at Flagstaff in 1994, and 
    was given every assistance with regard to the Observatory's archives. On 
    several occasions Leonard gave valuable advice to both the BAA and ALPO.
    D: 14".1 to 13".9 (14".2 at opposition on Mar 17; closest approach Mar 20),
    Ls: 91 to 98 deg. New contributors were Arthur Bowyer, Andrew Farr, Alan
    Heath, Michael Hendrie, Lee Macdonald, Dr Patrick Moore, Dr Stewart Moore,
    David Strange and Peter Wade in the UK, Emilio Colombo in Italy and Gerard
    Teichert in Frnce. Thanks also to Wolfgang Meyer for German Mars observations.
    UK weather and seeing conditions were often good. Check out the incredible new
    HST images on the WWW if you can, at:
    North polar region:
    No N. polar haze was evident in white light. Schmude on Mar 27 found a small
    detached part of the cap near long. 340 deg (probably the same feature
    observed by Devadas on Mar 7). Olympia was well shown in the CCD work by Dijon
    and Strange, and visually by Fisher and McKim. Hyperboreus Lacus was widely
    observed, and from it extended a thin dark fringe to the NPC covering a wide
    range in longitude. Warell reported a difficult, N-S rift in the cap on Mar 23
    (CML 244 deg., 16-cm OG) and 24 (CML 246 deg., 36-cm OG).
    Surface features:
    Much fine detail has been drawn and imaged, despite the small size of the disk
    at opposition. In excellent seeing Cave could see Juventae Fons. The southern
    regions were still foreshortened but Solis Lacus clearly remains large and
    dark; no internal details have been detected. No-one has reported Phasis this
    apparition, but it is a delicate feature even when the presentation is
    favourable. Likewise Gallinaria Silva, the 'oasis' at the N. end of the
    latter; this has probably faded. The Melas Lacus-Tithonius Lacus complex is
    rather dark. The OAA drew attention to the lack of redness in Thaumasia
    compared with Daedalia-Memnonia-Amazonis. CCD work by Strnage and visual work
    by Warell suggests that the Nodus Alcyonius is faintly joined to S. Utopia by
    a half-tone shading; this area also darkened between 1982 and 1984, before
    fading again.
    Dust storms (yellow clouds):
    There is nothing positive to report.
    White clouds:
    (A few interesting points, not a complete account; w.c. activity remained
    high.) Small white clouds were seen on the borders of Nilokeras by Cave 
    on Mar 19 (between Niliacus L. and Achillis F.) and 21 (W. Tempe). Tempe was
    generally not very bright near mid-disk but was light in the morning and
    evening. Hellas remained very bright, especially in its NW (Nf.) corner. A
    large cloud habitually covered Libya-Isidis R. on the morning terminator. 
    A wide general 'Blue Clearing' is apparent from several observers' work.
    Richard McKim, Director
    1997 April 19th
    fax and answerphone 01832-274052; home telephone 01832-274553
    email address
    Back to Date Menu

  • March 1-15, 1997

    Mars, 1996-97: British Astronomical Association:
    Seventh Report on observations 1997 March 1-15
    D:13".2 to 14".1. UK weather improved. Jean Dijon joined the BAA team.
    North Polar region
    No N. polar haze was evident (Int. light). Hyperboreus Lacus, Rima 
    Borealis and Olympia were still visible.
    Surface features
    As earlier. The disk has now reached maximum diameter, so please observe
    intensively over the next few weeks. The Director could glimpse the complex
    mottled structure of Mare Acidalium in fine seeing; the Mare seemed darkest
    on the Nf. side. Niliacus Lacus was large and Achillis Pons obvious. Fine
    details in the nearby deserts were also caught, such as a half-tone shading
    marking the S. part of classical Gehon. To the north, Iaxartes connected 
    Mare Acidalium to Hyperboreus Lacus.
    Dust storms (yellow clouds) and White clouds
    Re. the possible dust storm over Tempe alluded to in Circular No. 6, Jim Bell
    informs me that this was suspected by Dr Leonard Martin on Feb 14 and 15.
    However, IRTF data on Feb 16 and 17 show no dust. Tempe has not been
    especially light on the morning side, but Devadas found a bright afternoon
    cloud over Tempe on Mar 2 (under CM 86 deg.) as well as a small, bright cloud
    over Alba on the a.m. side. None of the BAA observers reported dust in Tempe
    in February or March.
    White cloud activity is now quite marked. The areas described in the
    last report remained active, with Chryse and Xanthe both exhibiting a.m. and
    p.m. cloud. On Mar 3 Knott (22-cm refl., CML 61 deg.) saw a very bright
    discrete white patch on the a.m. limb over Olympus Mons, visible in blue, but
    not in red light. The orographic clouds over the Tharsis volcanoes and 
    Olympus Mons continued to show up clearly on the evening side. The Director
    on Mar 10 and 11 saw Argyre (I) whitish on the morning limb (surface 
    frost?),  with white cloud over Tharsis-Ophir-Candor: the latter 
    white cloud extended further onto the disk by running along the S. part of 
    classical Xanthe. Indeed, white cloud upon mid-disk tended to extend 
    east-west along the equatorial border of Sinus Sabaeus (with Edom 
    sometimes separately bright). A number of reports of the 'equatorial cloud 
    bands' (ECB) have ben received. Thus with Syrtis Major near the evening 
    terminator, evening cloud over Aeria has been thought by some observers to 
    be thinly connected to morning cloud over Chryse/Xanthe by a bright E-W 
    streak approximately along the martian equator. However, some such 
    observations are simple optical illusions. The Director on Mar 10 and 11 
    under CML circa 20 deg. did not see ECB connecting the morning and evening 
    bright patches. Objective wispy ECB clouds were imaged by the HST in 1995, 
    and by visual observers for many years previously. Most recently Troiani 
    on Mar 12, CML 65 deg., reported an ECB connecting evening cloud with morning 
    cloud over Memnonia and Tharsis. Southern limb haze was also present. Troiani 
    remarked that a large number of thin white clouds were partly veiling the albedo
    features. HST images in 1995 showed wisps of white cloud crossing M.Acidalium
    and thus reducing its intensity. The foreshortened Mare Sirenum may be
    affected by the haze present along the S. limb at some CML.
    Future European Missions to Mars
    ESA publication D/SCI/96(2), Intermarsnet: Report on the Phase A Study,
    considers the scientific benefits of a network of martian groundstations. The
    study is based upon the 2003 launch windows for the ESA M3 opportunity; the
    idea is to place three groundstations in a triangle of side 1000 km. 
    Proposed sites are: A; Gusev crater [in classical S. Zephyria] at lat. -15 deg.,
    long.  184.5 deg., alt. 0 km; site B: Uranius Patera plains at +29 deg., 93.5 
    deg., alt. +1 km; site C: Coprates highlands [S. Xanthe] at -2 deg., 49.5 deg.,
    alt. + 2 km.
    Emailing the Director
    My email facility will not be accessible to me during Mar 22 - Apr 17. Fax,
    write or phone!
    Richard McKim, Director
    1997 March 19th fax and answerphone 01832-274052; home telephone 
    Back to Date Menu

  • February 16-28, 1997

    Mars,1996-97: British Astronomical Association:
    Sixth Report on observations 1997 February 16-28
    The disk diameter increased from 12.0 to 13.2 arcseconds. New contributors
    were Mrs Elisabeth Siegel (Denmark), Mrs Komala Murugesh (India), Giovanni
    Quarra and his colleagues (Italy), and David Fisher and John Knott in the UK.
    Extremely bad weather conditions prevailed in the UK. Circulars No. 4 onward
    appear on the new BAA Mars Section Web page, courtesy Jim Bell of MarsWatch
    (, and are emailed to those able to
    receive them. Other observers receive them by post when the Director
    acknowledges observations. Observers should check the Web site  for remarkable current hi-res IRTF images
    by Bell and colleagues. Section members are now showing more detail in their
    drawings. Devadas has supplied the largest number of observations so far, and
    special credit must go to Quarra and colleagues for superb CCD work at five
    wavelengths from the ultrraviolet to the infrared; examples are attached
    [paper copies of this Circular only].
    North Polar Region
    The North Polar Cap was quite small, about 20 degrees across. Devadas made
    out the bright detached outlier Olympia. Warell reports clear skies from La
    Palma on Feb 22-23 and the observation of a rift in the cap around long.180
    deg (the p. end of Rima Borealis?). Hyperboreus Lacus continued to be
    prominent, marking the only remaining really dark part of the NPC border. No
    sign of polar haze was detected in white light, though images by Quarra et al.
    , on Feb 8 and 9 in UV (330 nm) and B (420 nm) showed haze over the cap. In
    1982 the BAA Mars Section found the onset of the polar hood about Ls = 152
    degrees, and at 161 degrees in 1984. (Ls is 92 degrees at opposition on Mar
    17.) Observers should pay special attention to this region. The Section
    received an email alert from M.Murakami of the OAA that under CML = 194-204
    deg. on Feb 10 (Ls = 76 deg.), Minami and Nakajima found the following quarter
    of the cap more dull and yellow than the rest. Seeing was good. On the same
    date from the UK under CML = 270 deg., Shirreff (25-cm OG, poor seeing) found
    nothing odd about the cap, and Cave (Long Beach, USA, 32-cm refl., x660) on
    Feb 10-16 under CML = 323-26 deg., in very fine seeing found the cap uniformly
    sharp and bright, with a notch in the longitude of M.Acidalium (long. approx.
    30 deg.). Quarra's multi-filter images (Feb 8-9, CML approx. 280-3550 deg.)
    showed Olympia well, but no tonal differences. Later BAA observations under
    the same CM longitudes viewed from Japan were all negative. More details of
    the Japanese observations were given in the OAA's CMO No. 185: red light CCD
    work on Feb 8 apparently also showeds the effect under CML = 191-200 degrees.
    Surface features
    The HST images are available on the MarsWatch Web site. The Director has
    studied these closely. The images of Mare Acidalium in December are almost
    indistinguishable from those in 1995. No largescale dust activity can have
    occurred since then, despite a report from Todd Clancy back in 1995 December
    which suggested that dust was then widespread as indicated by CO microwave
    observations. A copy of the BAA 1992-93 apparition map is attached to this
    Circular together with a printout from the Web of the long. 45 deg. image
    cited above [paper copies only]: the close resemblance between these
    apparitions will be at once apparent, so there is little need for a further
    description here except to add that the far northern regions can be better
    observed this year. Note that Pandorae Fretum remains dark.
    Dust storms (yellow clouds) and White clouds
    Jim Bell emailed the Director to draw attention to a fine NASA IRTF image from
    Hawaii now posted on the Internet. This was secured by Bell and others on Feb
    17.Tempe appears normal in the near-IR at 2.331 microns (CML = 43 deg.),
    though Bell suggested that Dr L.J.Martin (Lowell Observatory) had recently
    seen a possible brief dust event there a few days earlier: more details have
    been requested by the Director.
         Xanthe remained rather bright both at the evening terminator and on the
    morning limb; clasical Chryse less so. It seems that the martian sky is clear
    over the Pathfinder landing site. Tharsis, Thaumasia and Sinai (IAU) have all
    appeared bright on the morning limb, and the Tharsis orographics were most
    prominent near the evening terminator. HST pictures show the clouds'
    appearances varied on a minute scale between images during September to
    January. Aeria and Tempe have exhibited diurnal cloud, too.
         Elysium has shown up bright in whole or in part on the evening side as
    well as when rising. Hellas was dull white to Sturdy under CML = 268 deg. on
    Feb 15. Hellas was bright on mid-disk to Schmude on Feb 23; he could glimpse
    Hellas through the W47 (blue-violet) filter, but no albedo markings were seen.
    Schmude found Hellas especially bright (at most visible wavelengths) when it
    was on the morning limb. Siegel (20-cm SCT) on Feb 2 under CML = 6 deg. also
    estimated the Blue Clearing as 0. Quarra's images (Feb 9) showed a UV/violet
    cloud over the location of Syrtis Major that rotated with the planet. Dark
    markings in violet light did not correspond with albedo features. Would
    observers please comment on the 'BC' effect? I have had few remarks about it
    so far.
    Richard McKim, Director
    1997 March 12th
    NEW email address
    fax and answerphone 01832-274052;  home telephone    01832-274553
    Back to Date Menu

  • February 1-15, 1997

    From Mon Feb 17 13:48:40 1997
    Mars, 1996-97: British Astronomical Association:
    Fifth Report on observations 1997 February 1-15
    The disk diameter increased from 10".6 to 12".0. New contributors were Mrs
    Sally Beaumont, David Storey and K.M.Sturdy (UK), and ALPO Mars Coordinator
    Carlos Hernandez (USA). No attempt has been made to analyse all the
    observations submitted, some of which relate to earlier months (!).
    North polar region:
    The North Poalr Cap retains its dark collar but is shrinking appreciably all
    the time. There are indications thgat it is slightly asymmetric about the
    rotational pole. Schmude (15-cm refl.) found the cap rather dull under CML 
    185 deg. on Feb 1, but Warell under CML = 71 deg. on the same night found it
    bright. Hyperboreus Lacus is now visible near the NPC; Ishadoh (OAA, Jan 31)
    reported the observation of Olympia.
    Surface features:
    Devadas (36-cm refl.) found Meridiani Sinus well marked, but the prongs of
    Dawes' Forked Bay were not well separated, the region between them being
    shaded. Both Devadas and the Director could see the streak of Deuteronilus
    well-marked to the north. On Feb 8 the Director found the E. end of Sinus
    Sabaeus just as it appeared in 1995, with Deltoton Sinus still faded.
    Nepenthes was invisible. Warell saw Ganges dusky, but paler than Nilokeras.
    Achillis Pons is a half-tone. Solis Lacus is dark, as are Melas Lacus and 
    Oxia Palus.
    Dust storms (yellow clouds):
    In an email dated Feb 11, Jim Bell, MarsWatch Coordinator notes that "dust
    activity is remaining rather minimal" and goes on to write that as the
    American probes get closer to their encounter dates, NASA "will be getting
    more and more nervous about dust opacity, as this will affect the entry and
    operations of Pathfinder an the aerobraking manoeuver of Global Surveyor."
    In CMO 184 M.Minami (OAA) queries the source of my statement in BAA Mars
    Circular No. 2 that Parker imaged the September 18 dust storm. I quote from an
    emailed November ALPO Mars Circular (which had also been sent to the OAA): "On
    Sept. 18, 1996, Don Parker, with help from Carlos Hernandez, imaged a dust
    storm that was associated with the NPC." In the same CMO it is reported that
    G.Quarra et al. (30-cm Cass.) obtained infrared CCD images showing that NW
    Elysium apparently contained a small dusty patch on Jan 17. BAA visual data
    for mid-January do not show this brighter area at lower resolution. Hernandez
    emailed the Director to report a suspected dust storm in Thaumasia on Jan 29
    under CML = 132 deg: Solis L. was seen to be surrounded by a bright region in
    red, but not in blue light. However, no obscuration was shown on his drawings,
    and the region was adjacent to very bright S. limb haze. CCD images by Parker
    on Jan 29 and Quarra on Jan 31 showed no dust activity, whilst BAA visual
    observations by Devadas, Gray, Storey and Sturdy (Jan 20-26) show only white
    morning and evening cloud over Thaumasia, so it must be concluded that there
    was no storm. The brightness of Thaumasia at this season is typical: see the
    1980 and 1982 BAA Mars Reports.
    White clouds:
    The morning limb showed more diurnal cloud than the evening terminator. The
    Director on Feb 8 (22-cm refl., CML = 306-315 deg.) found Libya-Isidis Regio
    quite bright at the evening terminator, but Hellas to the south was not
    conspicuously light. On Feb 1 (CML = 71 deg.) Warell (45-cm refl.) saw a broad
    a.m. limb haze with a local brightening over Olympus Mons. Devadas failed to
    see Edom as a separate bright area but several times found the general N.
    border of Sinus Sabaeus rather bright, perhaps affected by light hazes. 
    Edom-Thymiamata was light to McKim on the morning limb on Feb 8. Chryse 
    remained rather bright both at the evening terminator and on the morning limb.
    Richard McKim, Director
    1997 February 16th
    Back to Date Menu

  • January 1-31, 1997

    From Mon Feb 10 13:45:24 1997
    Mars, 1996-97: British Astronomical Association:
    Fourth Report on observations 1997 January 1-31
    The disk diameter increased from 8".0 to 10".6. I refer to published OAA
    data (CMO No. 183) for comparison. New contributors this month were
    P.Devadas (India), Prof. C.M.Gaskell (USA) and C.Meredith (UK). Others are
    known to have unreported observations! The NASA probes are en route, but Mars 96, 
    the Russian one, failed; the latest details have been given in Sky and
    Telescope, 1997 March, page 20 and elsewhere. William Sheehan's excellent
    new Mars book is also reviewed in the latter magazine.
    North Polar Region
    The North Cap remained large and bright to all observers, with a dark collar.
    No colour other than white has been directly reported to the Director in the
    period reviewed, but in CMO No.183 H.Ishadoh (31-cm refl.) is reported to
    have noticed a slight dullness coupled with a brownish tint "from November or
    before", until Dec 16. The Japanese account fails to mention any particular
    CM longitude (or CML range), which may be important. From Dec 24 the cap
    seemed normally bright again to Ishadoh; the brownish tint partly confirms
    Schmude's December 20 observation (see BAA Report No. 3). Few UK observations
    for December are to hand; they reveal nothing unusual (nor do the other
    Japanese data). Devadas commented that by Jan 14 the NPC seemed perceptibly
    smaller than earlier, which is to be expected from the seasonal date. 
    The Director has not yet measured any of the images submitted for latitude.
    Surface features
    In the second half of December and the first half of January, OAA observers
    remarked upon the colour contrast between the bluish maria to the south and 
    the brownish Utopia to the north. Doubtless these apparent tints will differ
    from their true colours, but the difference in hue is undoubtedly real. This
    difference has been remarked upon very many times by past observers at
    aphelic apparitions: for example, the BAA Mars Section in 1935, Mottoni
    in his beautiful coloured charts for 1952, Capen in the 1960s, Antoniadi and
    Slipher in their observational notes, and in the seasonably comparable epoch
    of the early 1980s by the BAA and other organisations. Devadas (36-cm refl.)
    on Jan 20 saw Solis Lacus well: it was quite large and dark, as in 1995. (Is it
    finally fading again on the southern following side, as noticed in the 1995 CCD 
    images?) Tithonius L. and Phoenicus L. were also well-marked. Devadas and
    Meredith found the foreshortened Mare Sirenum somewhat poorly defined. Some of
    the martian volcanoes have shown up on mid-disk as dusky spots this month.
    Dust storms (yellow clouds)
    The deserts appeared their characteristic light orange, dust-free colour.
    White clouds
    Examples only, given that many observations still remain unreported: Devadas,
    Jan 4, CML 253 deg., Elysium lightish preceeding the CM; morning cloud over 
    N. Aeria-Arabia. Devadas, Jan 14, CML 157 deg., Elysium lightish on the morning limb. 
    [OAA observers found Elysium quite dull or only slightly light on the evening side 
    (late Dec to early Jan), but light to the west of Propontis I, when immersed in the a.m. 
    limb haze (mid-Jan). They found Alba apparently variable; in mid-Jan it was sometimes 
    lightish from midday to evening]. Devadas, Jan 20, CML 96 deg., Chryse-Xanthe bright on 
    evening terminator, and Arcadia-Tempe lightish on mid-disk. Warell emailed the Director 
    that the Tharsis orographic clouds were "very evident" on Jan 24.
    Back to Date Menu

    B.A.A. Mars Reports

    Page maintained by Jim Bell
    Mail to: