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Phobos
Phil Stooke
post Nov 21 2006, 01:33 AM
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Good point, Ted - actually I'll be reducing it to 8 bit after a judicious contrast stretch (actually 2 different contrast stretches merged), and then saving it as a high quality jpg, so it will be compressed, but a lot less than my post.

Phil


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Phil Stooke
post Nov 21 2006, 01:38 AM
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Here's another one... orbit 748.

Phil

Attached Image


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elakdawalla
post Nov 21 2006, 02:17 AM
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Oh, that's a nice one, Phil!

Are you methodically posting every halfway decent Phobos image here or are you just making selections of your favorites?

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Phil Stooke
post Nov 21 2006, 03:30 AM
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I'm not being methodical, I'm just playing. I needed a break from more serious stuff. But I'll probably end up posting any decent Mars Express pics as I find them.

Phil


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Ian R
post Nov 21 2006, 11:29 AM
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Good grief! Is it my imagination, or are there really two sets of grooves in the image that Phil just posted, intersecting at right angles? blink.gif

How does this tally with the theory that the grooves were produced by interactions between Phobos and debris in orbit around Mars?

Ian.


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edstrick
post Nov 21 2006, 11:37 AM
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Despite impeccible logic and analysis "proving" how the grooves were formed by impacting debris, I just don't believe it. Yah... one group from 10:00 clock to 4:00 clock and a second finer set from 1:00 clock to 7:00 clock angle. _AND_, roughly bisecting them at an angle of 5:30 to 11:30 clock angle is a non-groove linear splatter pattern that looks like it *IS* splatter-cratering from a jet of debris.
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Ian R
post Nov 21 2006, 11:45 AM
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Good catch on the splatter pattern Ed. That certainly does look more like a crater chain from a debris or cometary impact.


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Phil Stooke
post Nov 21 2006, 02:20 PM
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Here's a link to the higher quality Phobos image posted above. It's reduced from 16 to 8 bit, cropped and saved as a high quality JPG, so it is compressed but not too badly. The 16 to 8 conversion was done twice, once to favour dark areas, and the results merged using my secret sauce recipe. I'll keep this up here for a few weeks and then remove it so get it while it's hot.

Phil

http://instruct.uwo.ca/geog/136a/hrsc756_phobos.jpg


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elakdawalla
post Nov 21 2006, 05:48 PM
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I've mirrored it here...
http://s3.amazonaws.com/planetary/10212/hrsc756_phobos.jpg

--Emily


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volcanopele
post Nov 21 2006, 06:36 PM
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Phil, do you know the pixel scale on that particular image from orbit 756?


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Phil Stooke
post Nov 21 2006, 06:55 PM
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The PDS label says 5.9 m/pixel. and roughly 5000 pixels across 30 km seems to support that value.

Phil


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dilo
post Nov 21 2006, 09:03 PM
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Thanks for the great image Phil, I hope one day you will reveal your secret sauce recipe... wink.gif
(I was wrong about image scale because I estimated it using Phobos mean radius instead of diameter)


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Phil Stooke
post Oct 14 2007, 02:18 PM
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Here's a nice new Phobos image from Mars Express, orbit 3909:

Attached Image


Phil


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scalbers
post Oct 14 2007, 02:29 PM
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Out of curiosity, how are things going with mapping of Phobos? The best global map I've seen is the USGS airbrushed version. FWIW, my mapping software is approaching the point where I can consider utilizing more general shape models, vs a simpler triaxial ellipsoid.


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Phil Stooke
post Oct 14 2007, 05:04 PM
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I should have added to my previous post - it came from one of the abstracts at the ESA Mars Conference - see thread under Conferences. Willner et al., in the Friday Workshops.

Mapping - there has been no serious work since Viking. I've been saying for years that I'll make a new global mosaic with the best images, but other things have prevented me. But I will certainly do so when Phobos-Grunt flies, or if CSA's PRIME gets funded. The abstract above refers to a new global shape model, which will help improve the next round of mapping.

Phil


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