Dawn Survey Orbit Phase, First orbital phase |
Dawn Survey Orbit Phase, First orbital phase |
Jul 17 2011, 09:09 AM
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#1
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
I think it's time we start a new thread
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Jul 21 2011, 10:23 PM
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#2
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Member Group: Members Posts: 723 Joined: 13-June 04 Member No.: 82 |
Has anybody looked at the effects of geometric perspective? Dawn is now close enough to Vesta that it should show a somewhat greater angular diameter as seen from Dawn than you would expect by simply dividing Vesta's diameter by its distance from Dawn. Vesta's edge, as seen by Dawn, is actually slightly closer to Dawn than the "great circle" perpendicular to the line connecting the centre of Vesta with Dawn, which would be slightly smaller as seen by Dawn (if it could be seen through solid rock). Therefore the number of pixels from one side of Vesta to the other would be slightly more than calculated using Vesta's diameter, and its distance from Dawn.
I do not know if the difference would be enough to account for the discrepancy described earlier, but somebody could check? |
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