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Exploring LROC NAC images
Phil Stooke
post Sep 19 2010, 01:35 PM
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Cassioli, it does not work that way. The coordinates are only a very rough guide. Typically, for previously unseen impacts like Ranger 6, the coordinates might tell us which 25% of the height of an image to look in, but it might lie in that image or in one on either side of it. The uncertainty is very great. Researchers are looking for a very fresh-looking crater with distinctive crater morphology, somewhere within that region of uncertainty. It is of course different if we have previous images of the site. For instance, Ranger 9's crater was seen by Apollo 16 (and the impact point was seen before impact by Ranger 9 itself). There, we know exactly where to look, but not from the coordinates. After it's found, the true coordinates are found by interpolation from the corner coordinates, which are themselves calculated from the spacecraft location and pointing estimates.

Phil


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... because the Solar System ain't gonna map itself.
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Juramike
post Sep 20 2010, 11:44 PM
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(Crosslink to a more detailed explanation of flipping and coordinates by Phil on another thread here. Thanks, Phil!)


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Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Phil Stooke
post Jun 28 2011, 02:08 PM
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Here's a pic of a curious feature I had poinrted out once before, but with different images. A sort of Ina-like feature in Mare Tranquillitatis. There are more of these in Hyginus. How many more will turn up, I wonder?

Phil

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Phil Stooke
post Jun 28 2011, 02:21 PM
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... and here's another one not far from that one (note coordinates at lower right). This one is a new discovery.

Phil

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john_s
post Jun 28 2011, 03:31 PM
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The first of those, at least, looks to me like a kipuka (I just wanted an excuse to use that word- Hawaiian for "a depression between surrounding lava flows"). The terrain inside the depression seems unremarkable- just a region that happened not to be covered by the last lava flow. The flow fronts do look remarkably fresh, though. The second one I'm not so sure- hard to tell given the lighting but there seem to be some unusual textures in there.

John
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