LtE in CMO #285

From Richard J McKIM



« . . . . . . .Date: Sun, 14 Dec 2003 05:06:56 EST

Subject: Re: DPk Dust Alert - CMO Notice #07

 

Dear Masatsugu:

 

I received the alert from yourself and Don Parker. The planet will be low in the west for UK observers to detect any dust at the morning terminator but we shall try. The event recalls 1990 November, and I suppose it will be limited to a large regional event.

 

In the absence of CMO I have kept up to date with your website. Ours at the BAA is also updated regularly.

 

This year I have been very busy with several major historical biographies, and also the deskwork for the present apparition. Not to mention that our daughter Michelle Anna McKim was born in April!

 

Now I have made a start upon the backlog of final apparitional reports, and hope to complete the 1995 report begun some time ago. It will be followed up as soon as possible with the 1997-2003 reports. I will be very glad to have any drawings from you for 2001 and 2003, and xerox copies of any notebook pages will be very welcome. I think I have specimens of your drawings for the earlier years.

 

I have had so many CCD images this year I could not even find time (yet) to count them all! There were 114 observers.

 

I understand that you have not been well, but hope you nonetheless enjoyed the Great Perihelic Opposition of 2003. Please accept my best wishes for the season, and for 2004.

 

Yours sincerely

 

« . . . . . . .Date: Tue, 16 Dec 2003 04:30:04 EST

Subject: Re: DPk Dust Alert - CMO Notice #07

 

Dear Masatsugu

 

This is a short reply to your long email, for which many thanks. I am just quickly looking at my email before going shopping.

 

First, the download failed to work because it told me that the specified filename is invalid. I wonder if you could try again? AOL can be difficult.

 

Despite the south declination I made 133 drawings to date, and over half are good ones.

 

The present storm recalls 1990 November in many respects. And I would predict it is seasonally too late to become encircling. Last night from here Hellas did not look dusty to me, but we cannot see the Chryse (etc) storm longitudes from the UK.

 

I owe you a longer reply!

 

Best wishes for now

 

 

« . . . . . . .Date: Tue, 16 Dec 2003 10:15:00 EST

Subject: Re: DPk Dust Alert - CMO Notice #07

 

Dear Masatsugu

 

Thank you. This time, fine, and indeed most impressive. I would be glad to publish this collage later. It fills a gap in our coverage of this event.

 

I understand what you write about older work. I have 16 boxfiles of data to analyse from the period 1995 to date, comprising an average of 100 observers and 3000 observations per opposition. My regular reports were interrupted by the completion of the dust storms book, but I have the 1995 work on my desk now.... Nonetheless I will glad to make use of xerox copies of your sketches, especially if you do not intend to publish them yourself. As you know, I am, and will remain primarily a visual observer.

 

All the best

 

« . . . . . . .Date: Wed, 17 Dec 2003 05:02:50 EST

Subject: Re: Mars Images

 

Dear Don

My thanks for these nice images. I am sending the (delayed and updated) BAA Mars circular about this storm below, in case I did not send it earlier. The event's spreading further to the east now somewhat resembles the 1988 November regional event, although its origin was more like 1990 November, both of which are detailed (and charted) in my dust storms book.

 

All the best

 

............................

 

Martian dust storm: Chryse-Argyre-Thaumasia

 

A regional dust storm has broken out on Mars. Dr Donald Parker (USA) writes of his CCD images taken on December 13 (Ls = 315 degrees): "A significant dust storm has arisen to cover Chryse, ErythrŠum M., AurorŠ Sinus, Candor, with smaller clouds in northern Argyre and possibly Aram." On December 9-10 Chryse and Candor were bright, especially in Parker's red light images, but no definite obscurations were present. Typically storms in this region break out in eastern Valles Marineris or in southwest Chryse (classical SW Xanthe). Data from December 14-16 indicate a spreading of the dust to include part of Thaumasia.

 

Bad weather has plagued observational work in the UK throughout December to date, but it can stated that CCD images by Michael Foulkes on December 5 show the region to have been normal then, whilst images by Damian Peach on December 9 and drawings by the Director on December 15 show the longitude of Hellas to be normal too. Visual work by Gianluigi Adamoli (Italy) on December 3 provides further confirmation, as do drawings by Gerard Teichert (France) on December 7-9. (This shows the value of routine work, which far too many observers have already abandoned!)

 

The seasonally latest planet-encircling dust storm known began at Ls = 311░ in 1924 December, suggesting that the present event will not exceed large regional status. The December 13 images recall a similar regional event in 1990 November.

 

Mars is well-placed for northern temperate observers, although good seeing will be needed to identify features upon the small disk. From western Europe, only the eastern end of the dust-affected region can be presently seen at the morning terminator with the planet well past the meridian, but the storm longitudes will be better placed for viewing later as they become visible over the evening limb.

 

Richard McKim,

Director, BAA Mars Section, 2003 December 16.

 

 

« . . . . . . .Date: Tue, 23 Dec 2003 15:37:39 EST

Subject: Mars dust storm activity: latest news from the BAA

 

Cherry Tree Cottage, Upper Benefield, England

Almost Christmas Eve, 2003

 

CHRISTMAS PRESENTS FOR MARS:

A BEAGLE AND A REGIONAL TELESCOPIC DUST STORM

 

"I'm dreaming of a white Christmas....."

 

[If we substitute 'dusty' for 'white', I suppose we can still imagine Bing Crosby singing this in the snow...... but it wouldn't be so photogenic!]

 

 

In advance of a report to be written for the 2004 April BAA Journal, I am writing to give a few details of the recent significant martian dust storm, and to ask if anyone receiving this email letter has further observations to contribute.

 

Reports of the BAA observations up to the present are given on our Mars Section website at:áá http://www.britastro.org/mars

 

On the night of December 12/13 UT (at Ls = 315 deg.) CCD images by Don Parker showed that a significant dust storm had arisen over southern Chryse (telescopic southern Xanthe) and the eastern part of Valles Marineris. Smaller, secondary dust cores were seen in northern Argyre and over Aram. (It seems that this really was the first day of the storm, but additional images from December 11-12 would be helpful.)

 

By December 13/14 a band of dust had extended SW from Argyre to higher latitudes and also westward across Thaumasia to the south of Solis Lacus (with the latter feature somewhat obscured). There was a general expansion of the original cloud to veil Eos-AurorŠ Sinus-Mare ErythrŠum.

 

On December 15/16, further images showed a belt of dust crossing Noachis and PandorŠ Fretum-Deucalionis Regio diagonally from Argyre, and impinging upon Sinus SabŠus. (Indeed, the Meridiani Sinus area was later affected by dust for a time.)

 

By December 17/18, activity was observed in Hellas in the form of a secondary bright core in the vicinity of the NW of the basin, its deepest part. However, the dust did not develop any further, probably having reached its maximum extent on this date. Observing visually, the Director (December 17/18 and 18/19, 41-cm Cassegrain, x410) detected a small projection of part of the Noachis dust cloud beyond the morning terminator.

 

A series of images by Ed Grafton at similar CML nicely demonstrated the progressive decline of the E. end of the storm during December 18-21. At the time of writing there remains but little suspended dust over Noachis, and the NW Hellas dust core is smaller and weaker. As of December 23, images by T. Akutsu (0740-0908 UT, CML = 63-85░W) show that the W. end of the activity has significantly declined, with the very little remaining dust in Thaumasia (just reaching the E. edge) connected to a bright persistent core in Argyre. Solis Lacus looks dark and well defined in these latest images.

 

There have been several albedo changes associated with the storm, and it will be interesting to see for how long they will persist. The PandorŠ Fretum area looks broader and darker, and Noachis is now somewhat less bright than before the event. The whole area around Depressiones HellesponticŠ (which marked the southern boundary of the Noachis dust) is much darker than before. A similar change occurred at the time of the great dust storm of 1956, and more recently during the event of 1988 November (see below). The Phasis area to the west of Solis Lacus should be watched closely for further possible albedo changes there as the dust gradually settles.

 

The general E-W extent of the storm at maximum was similar to that mapped by the writer for the 1988 November regional event, which had begun in Thaumasia to the south of Solis Lacus at Ls = 313░. However, in 1988 the activity ultimately did not quite extend as far east as Hellas. In its initial development, the present event began more like the regional storm of 1990 November at Ls = 326░. The Director actually cannot recall any historical event beginning in the location of the present one (S. Chryse-Xanthe/E. Valles Marineris) which showed such a considerable expansion in longitude! (Both the 1988 and 1990 events are illustrated and charted in R. J. McKim's monograph "Telescopic martian dust storms: a narrative and catalogue", published in Memoirs of the British Astronomical Association, Volume 44 (1999): see the Mars Section website for price and availability!) The Director (in BAA E-Circular No. 127) predicted that the event would not exceed regional status. This prediction was based upon the fact that the seasonally latest encircling storm ever observed had begun at Ls = 311░ (in 1924 December).

 

If you have sent Mars observations to the BAA in 2003 (as 114 people have done so far), let me take this opportunity to thank you again for your efforts and to assure you that the observational work will be fully analysed in due course. And remember that the apparition is not yet over!

 

Finally I am sure all BAA members would wish Beagle 2 a safe landing on Mars on Christmas morning and with that thought in mind let me send you my best wishes for 2004.

 

Richard McKim (Director, BAA Mars Section) 23.12.03

 


Richard McKIM (Peterborough, UK)

Director, the BAA Mars Section
email

http://www.britastro.org/mars


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