Dawn approaches Ceres, From opnav images to first orbit |
Dawn approaches Ceres, From opnav images to first orbit |
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#601
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Solar System Cartographer ![]() ![]() ![]() ![]() Group: Members Posts: 10196 Joined: 5-April 05 From: Canada Member No.: 227 ![]() |
On Tuesday (two days from now, for visitors from the future), the first optical navigation image will be taken... hopefully we'll have it in our hands soon after that. So it's time for a new topic. Over the next few months we'll have progressively closer images and full orbit characterization sequences, no doubt including multispectral image sets.
A new world... This is a bit of reprocessing I have been doing with the Hubble images from a few years ago. 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 PD: 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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#602
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Member ![]() ![]() ![]() Group: Members Posts: 107 Joined: 1-August 14 Member No.: 7227 ![]() |
Some images grouped and annotated:
![]() My processing of the bright-spot area of the DEM: http://lc84.altervista.org/vba4.stl It's just a quick-and-dirt 3d model, a bit more (just a bit) than a point-cloud; I'm working to get a surface instead, but what's very interesting is the altitude of the center of the crater: although I can't know the actual values of altitudes corresponding to grey levels, the relative altitudes are correct: ![]() |
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#603
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Junior Member ![]() ![]() Group: Members Posts: 48 Joined: 20-December 14 Member No.: 7370 ![]() |
My processing of the bright-spot area of the DEM: http://lc84.altervista.org/vba4.stl It's just a quick-and-dirt 3d model, a bit more (just a bit) than a point-cloud; I'm working to get a surface instead, but what's very interesting is the altitude of the center of the crater: although I can't know the actual values of altitudes corresponding to grey levels, the relative altitudes are correct: Great processing, but as others have mentioned, I think the saturated pixels in the crater obfuscate any real depth cues for the DEM algorithms. I think the the picture with the most value is the one in the rotation movie right before it goes out of view, that has the central spot unsaturated. From that picture it could be consistent with a floor with reflective ejecta spread around (the at 5-8% of the brightest pixel value). The little white spot peak is only 25% of the brightest pixel value so it's either likely a less albedo, or more likely - much smaller (3 adjacent 1/4 pixels). For the heck of it I tested the pixels in this image to try and get a better idea of what might be going on. % conversions relative to the brightest 242 pixel are here: 12 5% 20 8% 28 12% 44 18% 53 22% 60 25% 92 38% 100 41% 124 51% 132 55% 144 60% 163 67% 179 74% 194 80% 219 90% 227 94% 235 97% 242 100% |
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Lo-Fi Version | Time is now: 23rd June 2024 - 04:17 AM |
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