MOM At Mars, Mission Operations |
MOM At Mars, Mission Operations |
Oct 6 2014, 07:48 AM
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#31
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
...as we have seen from raw Mastcam and MAHLI images. ...is due to all the dust suspended in its atmosphere. Thanks Wildespace : quite good interpretation if I may say ! BUT, please remember that : 1) Mastcam images are in raw format and must be calibrated for their colors ; 2) Dust clouds from space looks indeed yellowish, not white. 3) The color of the planet from space, as you say, is not as yellowish brown as it is seen from the ground... |
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Oct 6 2014, 02:51 PM
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#32
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
I think this has resulted in colours very close to the colours of the surface as we have seen from raw Mastcam and MAHLI images. I remember reading in a few places that the pronouncedly red appearance of Mars when photographed from outside of its atmoshere is due to all the dust suspended in its atmosphere. Mastcam cameras have a well-known "greenish cast" making the surface look yellowish. If atmospheric dust reddened the planet, then the limbs should be redder than the centre of the disc, since you look through more dusty air near the limbs. Also the planet should look redder during global duststorms, but I haven't heard of a hue shift during duststorms. |
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Oct 6 2014, 04:22 PM
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#33
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Junior Member Group: Members Posts: 64 Joined: 17-December 12 From: Portugal Member No.: 6792 |
The surface color seen from space suffers the effect of the atmosphere 2 times. Light must come down and then back up.
So any hue will be magnified on full disk images, more so if there's dust or anything that absorbs / reflects light. The Red Mars from orbit is an accurate rendition of what you would see, the same way as astronauts see the Earth as a blue planet. If really doesn't compare to what it looks like on the ground . The limbs are also complicated because you have phase angle there. One thing is reflected light, another absorbed light, just to keep things simple. But you really have to take into account scatting, diffraction, etc, etc. Really not that simple. And on Mars you have limb hazes and clouds, so a bluish color is to be expected there. All this meaning that the MOM image is just fine. -------------------- www.astrosurf.com/nunes
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Oct 6 2014, 04:54 PM
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#34
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
Another factor is the seasonal variation in atmospheric dust - some seasons are far dustier than others, even in the absence of duststorms.
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Oct 7 2014, 12:04 AM
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#35
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IMG to PNG GOD Group: Moderator Posts: 2254 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Also comparing Mars's global color with the Curiosity images might not be accurate. In addition to light coming down through the atmosphere and getting reflected back out of it (as pointed out above) and seasonal variations in dust, Mars' global color isn't totally uniform (although color variations aren't big) and the Curiosity images show just one location on the surface.
Regarding Mars' color as seen through a telescope: There is a lot of orange color but I have found it to be orange with a slight pinkish tint as well but this is extremely subjective. Of the various versions of the MOM image I have seen, Don Davis' version is probably closest to what I have seen through a telescope in terms of color (but again, this is subjective). |
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Oct 7 2014, 12:26 AM
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#36
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
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Oct 7 2014, 11:01 AM
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#37
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Member Group: Members Posts: 378 Joined: 21-April 05 From: Portugal Member No.: 347 |
Completely subjective. And it changes with the telescope and magnification.
It's interesting that Mars seen with the naked eye (point souce) looks quite like Antares (that's why the star is called like that). That comparison seems to be valid for most people and since a long time. -------------------- _______________________
www.astrosurf.com/nunes |
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Oct 7 2014, 02:44 PM
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#38
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
Completely subjective. A measurement of spectral irradiance, ie the spectrum of incident light, is completely objective. Of course that's not what people are referring to when talking about telescope views. But it's worth remembering that, in principle, the "colour" of Mars could be measured and reproduced. In practice this would be extremely hard (no display devices exist to reproduce all, or a large part of, a visible spectrum, etc, etc...). The matter of subjectivity of perception is separate from this. But, getting back to the thread topic, it is easier to objectively discuss differences of colour. Long-term monitoring by MOM may tell us about seasonal variations on a global scale... |
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Oct 7 2014, 08:32 PM
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#39
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
A new MOM image of Mars has been released - see Emily's blog for the link. Here I compare it with the Rosetta flyby image. Lots of small changes to be seen, and much that is the same including the distribution of clouds.
I wanted to add a Hubble view and a Mariner 7 view (incredible changes since Mariner 7) but I don't have time. Towards upper right, a group of dark markings change very substantially. Look below them, there is a bright-toned curving patch on the surface in the Tartarus Montes area. That is where Mariner 4's first image of Mars was taken in 1965. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Oct 8 2014, 03:30 PM
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#40
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
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Oct 8 2014, 07:09 PM
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#41
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
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Oct 14 2014, 02:46 PM
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#42
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Senior Member Group: Members Posts: 1452 Joined: 26-July 08 Member No.: 4270 |
Phobos (animation)
https://mtc.cdn.vine.co/r/videos/B745972857...10491926854.mp4 -------------------- -- Hungry4info (Sirius_Alpha)
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Oct 15 2014, 10:03 AM
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#43
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Junior Member Group: Members Posts: 61 Joined: 20-March 10 From: Western Australia Member No.: 5275 |
Through my telescope (8" Newtonian) the Mars I have observed is similar to ugordan's
image. Only difference is the Polar Cap always appears very bright, white and sharp edged. Professional observations of Mars in daylight (sorry I don't have any links) reveal the planet to be a tan colour, markings brown to dark grey. Currently my scope is in pieces, gotta get it all together. Miss it. p.s. Never saw any canals |
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Oct 18 2014, 04:59 PM
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#44
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
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Oct 18 2014, 08:04 PM
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#45
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Forum Contributor Group: Members Posts: 1374 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
The last image from the Indian Mars Orbiter Mission ..... Do you mean the latest or the last one ? Did the mission end ? ADMIN NOTE: MahFl, I think that a quick look to either the mission website, Twitter feed, Facebook page, ISRO's website or any number of space news sites could have answered that question for you. MOM's mission continues as normal. At the very least check/Google before asking a quesion like that please. |
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