MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more |
MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more |
Jun 29 2013, 05:25 PM
Post
#31
|
|
Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
|
|
|
Aug 8 2013, 02:34 AM
Post
#32
|
|
Member Group: Members Posts: 866 Joined: 15-March 05 From: Santa Cruz, CA Member No.: 196 |
It looks like we might eventually get the full sweep between 3:02 and 3:04
So these must be stars in the 2:58 image centering on Deimos. Then after the close in exposure optimized shots of the transit, we pull back out with long exposure and see the stars again in the 3:05 image The stars in the long exposure shots appear to correspond perfectly with the stars in the subframe transit shots, so it appears Deimos is going the opposite direction as Phobos relative to the background stars! |
|
|
Aug 8 2013, 04:29 AM
Post
#33
|
|
Martian Photographer Group: Members Posts: 353 Joined: 3-March 05 Member No.: 183 |
Deimos and Phobos both orbit in the same direction, as you know. Deimos is far enough out that it (like our moon) has an orbital period longer than the planets rotational period, and its apparent motion is in the same sense as the stars. But it lags them, and does not change directions with respect to the horizon or the stars. Remember, Deimos is moving many times faster than the rover in an inertial, Mars-centered frame. Phobos is closer and faster, so it crosses the sky in the opposite direction, but just moves faster in the same direction with respect to the stars. So if they appear to move in opposite directions with respect to something, I would speculate the 'something' is not a star. Warm/hot pixels tend to be much more observable than stars for cameras optimized for landscape photos.
|
|
|
Lo-Fi Version | Time is now: 25th September 2024 - 01:32 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |