LtE in CMO #248,249

From Nicolas BIVER

@. . . . . . . . .Mars Storm under stormy weather! Storm under storm...that's a bit the way I can describe my only observation of the event, recently.


I don't know if you got some information from European observers, but our longitude should have favored the observation of the obscuration of Syrtis Major by the dust for the last 2 weeks.


Unfortunately I left France on July 1, so my last drawing in France was dated June 30.9 UT (see attached drawing) when Syrtis Major seemed hard to see close to the limb, likely partly covered by dust.


Since then, I got a telescope (25cm on the week-ends and 20cm in the week) to use after July 7, but weather did not cooperate much, either in France or in Noordwijk, Netherlands, where I finally got in touch with Mars on July 12.9 UT:


From there Mars culminates barely at 10 degrees above horizon (52.2 deg. N), and I actually observed it at 8 degrees (Second drawing)...For those who can get it 40 degrees high in the sky, I observe it through 4 times thicker atmosphere and turbulence!


Fortunately this Netherland countryside is flat like sea and seeing not so bad as wind is more likely laminary: On July 12.9 the seeing was good for what you would expect so low, fair to poor in absolute.


The problem was that sky cleared up (it took a bit longer to clear Mars low at the southern horizon) thanks to the wind of a storm system, blowing more than 60 km/h, and I had also the problem of not getting my scope blown away! [even behind (low) buildings I couldn't find some rest from these though windy conditions]


In any case, at CML 253, Syrtis Major should have been clearly visible (by comparison to a drawing of June 5 – see but was not identified although the NPC and Utopia seemed clearly identified (so not too much a seeing/wind shake effect). The SPC was tentatively seen small, also, most of disk being patches of low contrast albedo features, one likely related to Mare Cimmerium?


I wish you all better observing conditions for this on-going storm [on Mars, please not on Earth!!],         

 (14 July 2001 email)


@. . . . . . . Thanks for the update on Mars dust storm.

From France, mostly  (July14.9; 20.8; 21.8 and .9), plus July 16.9 from Noordwijk, I made a few drawings of Mars (I hope to find a way to scan then soon), with CML 140 to 218. The border of the NPC/NPH is the darkest feature, but the NPH may have been partially obscured by dust at some times (?).


M. Cimmerium seemed lightly and partially visible and M. Sirenum quite ill defined. There is actually a darker complex, roughly between Longitudes 80 and 120 and in the southern hemisphere (covering Solis Lacus - Aonius Sinus - Phoenicis Lacus - Tithonius Lacus (up to Tharsis?) region) that seemed a bit more obvious last Week-end (July 20.9-22.8), with lighter (storm clouds) patches to the South and at lower CML, apparently.


I have otherwise a more general question:


Although it has now been clear to all of us that we are watching a major global dust storm on Mars, why hasn't it be reported in an IAU Circular?


I don't know if it is usually done, but so far one was issued about the sighting of Edom flares in June, and none about the dust storm.

It may be now a bit late, but wouldn't it have been an opportunity to publicize amateurs (continuous) contribution in Mars observation to the astronomical community (even if it has also been monitored by some (MGS) professional means)?

What do you think?

(24 July 2001 email).


@ . . . . . . . Dear Masatsugu, CMO observers, I attach here some drawings I made of Mars while no so many feature were visible due to the dust storm...

 I will send more soon and prints by mail, as well as post them on my web page (in France, which is still the best way to reach me:

(2 August 2001 19:30:33 +0200 (MET DST) email)


@ . . . . . . . Dear all Mars observers, Here are 2 drawings made at CMLs (31-50) where much more should be visible, although Mars was only 11 degrees high in the sky from the Netherlands. I feel like there is a hint of Sinus Meridiani to Aurorae Sinus complex visible, but still not as dark as the border of NPH and Northern part of M. Acidalium.

 How long can we expect such a storm to last?  When was the previous major one of comparable extension and duration? [in the 70s? or some more recent than Viking 1&2  time]

(2 August 19:41+0200 (MET DST) email)


@. . . . . . . Please find here copies (actually color prints of ~100 dpi scans of the originals, that are available on my web page) of my recent Mars drawings since my last mail. Part of them now cover the large dust storm period that started a month ago, and although it is now hard to distinguish clearly any features (contrast are exaggerated on the drawings) it makes Mars even more fascinating, like a new planetary surface to discover!


On the other hand, I partly moved to Netherlands (52.2 degrees N) for my new job, and observing Mars from there is not so easy. Fortunately I get relatively good weather from mid-July until now, but the seeing can never be very good only 10 ~ 11degrees above the horizon. In addition my 20cm F/6 telescope brought to Noordwijk is on a low simple dobsonian- like mount, which makes the eyepiece something like 50cm above ground when observing Mars! - I nearly have to lay down to look through the eyepiece - but that is fine for not too long observing.


Now Mars is moving away from us, getting smaller and closer in the sky to the Sun. But viewing conditions shouldn't worsen any more during the next 5 months: I have noticed that it will transit always after sunset (which is happening earlier every day), during twilight though, until December! In addition, after September it will also get higher in the sky.


For now, I try to observe Mars as often as possible, watching the evolution of this major storm.

 Clear and Steady Skies,


(6 August 2001)

Nicolas BIVER (Noordwijk, the Netherlands/Versailles, Yvelines, France)

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