LtE in CMO #284

From Elisabeth SIEGEL

« . . . . . . . .Date: Tue, 2 Dec 2003 12:22:59 +0100

Subject: November drawings coming


Dear Masatsugu,


Yesterday I posted my November drawings to you, so they should hopefully arrive in a couple of days. Seven drawings was all that it amounted to in November - and I can tell you that I haven't missed a single clear evening, they're all there!


This time, for once, I think I may have observed something that may be of interest, as it seemed a bit out of the ordinary. It concerns the observations of November 19 and November 28; on both these occasions, I noticed a tiny, circular, really bright spot in W 47 on the morning side of the disk, quite close to the terminator, and near the north point of the disk. The November 19 spot was the most striking - it looked like some little, wildly misplaced polar cap, glowing whitishly on an otherwise quite dark W 47 background. (You'll find more details in the observing notes to these observations, of course.) At the time of each observation, I had no idea what these spots could be. But I have a very good Mars globe (from Sky & Telescope), so after each observing session I consulted the globe, taking care to reproduce the CM and tilt of each observation as correctly as possible - and found out (much to my surprise!) that the Nov. 19 bright spot seemed to coincide most nicely with the summit of Elysium Mons, whereas the Nov. 28 similar spot coincided just as nicely with the summit of AscrŠus Mons.


This really fascinated me, both because I've never observed the volcanoes before (at least not with any degree of certainty), and because I am not aware that they usually show up as bright on the MORNING limb. I have written a similar note to Richard McKim about these spots and got a quick reply, wherein he suggests that they may represent surface frost on the summits of the volcanoes, which sounds quite likely. (He hasn't yet received the drawings either, so he just reacted to my description of the spots in an e-mail.)


I would be immensely grateful if you could enlighten me on your personal opinion of these matters, once you've received and seen the drawings. Both bright spots were NOT just caught in glimpses or seen at the limit of visibility, but quite easily and steadily seen, so that I, personally, have absolutely no doubts about their reality. And they looked really strange!!


Best wishes to you and our OAA colleagues, yours sincerely,


Elisabeth SIEGEL (Malling, Denmark)


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