The Martian Sky |
The Martian Sky |
Oct 11 2009, 06:41 PM
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#1
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
I have been attempting to make computer generated images of the Martian atmosphere, both as seen from the surface and from space. To check the results I have been looking for spacecraft images to use as ground truth. I have found lots of images - by far the best ones I have found are from UMSF in this thread: http://www.unmannedspaceflight.com/index.php?showtopic=3324
However, I'm always looking for more ;-). So if anyone knows of more and/or better images I'm interested in them. What would be best are mosaics showing the sky from the horizon (with the horizon/surface visible) and towards the zenith. The sky varies a lot because of variable amount of dust but the general impression I get is that the sky is bright near the horizon (usually brighter than the surface) but gets much darker higher in the sky. There is probably a fairly large, bright area in the sky near the sun, possibly less reddish (lower R/B ratio) than parts of the sky farther from the sun. I'm already getting fairly interesting results, this one has a field of view of 90 degrees: (needless to say this one is 'overexposed' near the horizon; dynamic range is sometimes a problem) The problem is that even though this may not be bad the limb currently appears far too bright as seen from space : This shows that my atmospheric model is erroneous in some way - I suspect that as seen from the surface the Martian sky is darker high above the horizon than I have been assuming. |
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Jan 30 2018, 05:34 AM
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#2
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Member Group: Members Posts: 316 Joined: 1-October 06 Member No.: 1206 |
Hi all, OP here (at least in terms of Mars' sky at the zenith question).
Yes, I did mean during the daytime. This question was prompted by 2 things. 1. All the pre Viking paintings of Mars' surface that showed a thin blue band around the horizon. This came before we knew the amount of fines suspended in the atmosphere, but I always assumed that at 7mb, the sky directly above the viewer would be dark enough (assuming the Sun wasn't close in the sky) to see stars. Or would it be like the Moon, where glare and contrast extremes apparently made it near impossible for the astronauts to see stars? 2. Now add the fines we know are always there to some extent. Take a nice relatively dust free day at Gale (for instance) and look straight up. With the caveat about the Sun still standing, would you see butterscotch all the way to the zenith, with just the color slowly darkening - or would the sky be effectively black? And if it was black, what would be the chance of seeing say, a magnitude 1 star? P |
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