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
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#31
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
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Aug 16 2013, 06:11 PM
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#32
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
Phobos orbits so low that its angular size varies substantially depending on how far above the horizon it is - from something like 0.14 degree at the horizon to 0.2 degree at zenith. (I'm not sure if that corresponds to an average diameter or what.)
The press image doesn't show the long axis of Phobos as wide as the moon (0.5 degrees). Look at the Marsshine images and you'll see that most (about 2/3 or 3/4) of the length of Phobos is in sunlight in this image. So it shows the long axis at roughly 0.3 degrees wide. |
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