Going To Mogollon..., ...and points South |
Going To Mogollon..., ...and points South |
Mar 15 2006, 08:27 AM
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#241
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Senior Member Group: Members Posts: 1619 Joined: 12-February 06 From: Bergerac - FR Member No.: 678 |
Bye bye Erebus
... and, Victoria, Oppy arrives! -------------------- |
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Mar 15 2006, 06:16 PM
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#242
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Member Group: Members Posts: 198 Joined: 2-March 05 From: Richmond, VA USA Member No.: 181 |
QUOTE (Dilo @ March 13 2006, 05:51 PM) I do not see the feature you highlighted and I wonder about Crystal selection window... are colors associated to some kind of simulation you ran? The brighening is somewhat subtle, and easier to see if the unannotated and annotated images are compared side by side. The colors are from a simulation for some potential martian ice halo's (CO2 and H2O). (See: Halo Sim). Les and Michael were kind enough several years back to share their CO2 crystal files with me for a few projects I was working on at the time. As I was hurrying yesterday, the crystal settings are actually the same as used for Les' image posted here: Martian Halos. With respect the the brightening, I don't think a diffinitive answer can be made, as the brightening I noted could also be an optically denser patch of cirrus. More cirrostratus-like clouds would be better at presenting halos in nonmultispectral imagery (see: FIDO: 20020812164623_nav for example). Lastly, and again aganst these brightening being caused by any refractive phenomena, the brightenings that corresponded with the halo simulation were associated with CO2 cuboctahedron ice crystals, not haxagonal water ice cyrstals. My understanding is that these are water ice clouds. Any MiniTes measurements to the contrary? Longwinded (making up for yesterday ), but I hope that helps. -- Pertinax |
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Mar 15 2006, 09:27 PM
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#243
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Senior Member Group: Members Posts: 2492 Joined: 15-January 05 From: center Italy Member No.: 150 |
Thank you very much, Pertinax... I completely missed the Mars halos item, now I'm delighted and amazed by this argument!
I like very much also the site you linked (my preferred pages are this and this one). About your possible identification of "CO2 cuboctahedron ice crystals" halo, however, I hardly see it... from a strongly processed version of this image (where I removed very low frequency components) my impression is that you catched a cirrus, at least in the right portion... PS: based on this simulations, in the top-left image portion, shouldn't we see also some CO2 parhelia? -------------------- I always think before posting! - Marco -
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Mar 15 2006, 09:39 PM
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#244
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
-------------------- If Occam had heard my theory, things would be very different now.
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Mar 21 2006, 09:19 AM
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#245
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Senior Member Group: Members Posts: 2872 Joined: 22-April 05 From: Ridderkerk, Netherlands Member No.: 353 |
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Mar 21 2006, 02:46 PM
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#246
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Member Group: Members Posts: 198 Joined: 2-March 05 From: Richmond, VA USA Member No.: 181 |
Thank you very much, Pertinax... I completely missed the Mars halos item, now I'm delighted and amazed by this argument! <snip> About your possible identification of "CO2 cuboctahedron ice crystals" halo, however, I hardly see it... from a strongly processed version of this image (where I removed very low frequency components) my impression is that you catched a cirrus[.] PS: based on this simulations, in the top-left image portion, shouldn't we see also some CO2 parhelia? Sorry for the much delayed reply -- much of the family including myself were home sick last the second half of last week, and yesterday I was catching up at work. Concerning the image in question, I agree. The more and more I look at the cirrus, the less and less I think that there are any discernable halos. I'll be keeing my eyes particularly open when Oppy has her eyes up. For fun, I'll include another version of the image I poseted earlier. This 1) accepts the horizon as essentially correct (the simulation's horizon assumes an infinate, flat plane), 2) shows a bit more boldly the full possibility of potential halos for this view, and 3) shows the simulation's settings. Enjoy for what it's worth. Les' site on Atmospheric Optics is second to none. The 11Jan99 South Pole halo display is one of the greatest and best documented displays recorded. For better or worse, I had just missed (was first alternate) being at the pole as Meteorologist for the '98/'99 Austral Summer. The Saturn image was one of the projects that Les assisted me with. I have larger copies if you are interested. Cheers, -- Pertinax |
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