MEX VMC - Back on, and online! Options

[djellison]

I heard about this 24 hours ago, and couldn't believe it - this is EXACTLY what has been missing from ESA. MASSIVE kudos to the ESOC MEX flight ops team for doing it

http://www.esa.int/SPECIALS/VMC/index.html

The last time I wrote a post and hit 'submit' at UMSF with a smile this big on my face, was when Oppy successfully got out of Purgatory.

[ormstont]

Just to put my two cents in, you're right that the "object" fades a lot towards the end of the observation. It could well be that we're seeing something like the face on Mars - just a combination of light and shadow that looks like something we want to see. Nonetheless there aren't any major features I can see on the Mars map that would give rise to such a large flare/shadow. In ustrax's plot the crater identified is (I believe from looking at the Celestia file) Copernicus.

Using Ian Musgrave's Registax techniques he describes here http://astroblogger.blogspot.com/2008/08/w...-over-mars.html, combined with ugordon's colour processing script, I wonder if it's possible to clean up the image and see if we can place it more precisely on a map of Mars. Would be great to see what more it could teach us!

P.S. Top theories so far include trick of the light, cloud or (a long shot, but a cool one) an impact event plume...

[ustrax]

dear Ormstont, I am sorry to be a bit limited in terms of software for the moment but if that carter is indeed Copernicus then, looking at Google Mars, I see a bright patch to the right of the crater (marked) that could be the "culprit"...assuming that I am getting the right orientation and scale...

[ugordan]

It definitely appears to be atmospheric as the shadow moves below it (click to enlarge):


It seems to have dissipated at the end. Based on the rough 100 km size estimate I get a height in excess of 100 km (around 110 km, but the uncertainty is rather large) if my back-of-the-envelope calculation is right using this 3x magnified bit:


If it's an ordinary cloud, what would make it so circular at that altitude and would it dissipate quickly in sunlight? If it's an impact plume, wouldn't we expect a darker color and much lower and more persistent plume?

[siravan]

Based on the rough 100 km size estimate I get a height in excess of 100 km (around 110 km, but the uncertainty is rather large) if my back-of-the-envelope calculation is right using this 3x magnified bit:

How do you calculate the height? My back-of-envelop calculation based on the ratio and of the shadow to the object size and its distance from the object is more consistent with an altitude half the object size (50 km if the diameter is 100 km).

[ugordan]

Yep, it appears I messed up the calculation of (at least) illumination incidence angle using the shadow shape, I did an inverse tangent of a/b instead of inverse cosine of b/a. That, by itself, lowers the end result to some 80-ish km, which might still be wrong. 110 km was no doubt suspicious, being at upper fringes of the atmosphere.