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The power of HiRISE
ElkGroveDan
post May 11 2010, 04:32 PM
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I agree with Eduardo. Nick you of all people should know about avalanches. If you are unlucky enough to trigger one, the material both above and below you moves down the hill. Moreover, in this case it was more like those mortar shells that the ski patrol use to clear slopes. The airburst triggers the movement milliseconds before the object's impact over a broader area, both up and down the slope (and left and right). And from these images, that's what it looks like to me.


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climber
post May 11 2010, 07:44 PM
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I'll be interested to know how steep is the place. May be you know that on Earth, natural (snow) avalanches start at 30° and they may be are the most dangerous (since one wouldn't believe they can start with such a low angle).


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schaffman
post May 12 2010, 11:56 AM
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The dust avalanche is now featured at the HiRISE website:
http://hirise.lpl.arizona.edu/ESP_017229_2110
The location is in the Olympus Mons aureole (Lycus Sulci) not the slopes of the volcano as the earlier article indicated. This is an area of rough, highly jumbled terrain thought to be formed from huge gravity-slide deposits shed from the lower slopes of Olympus Mons. This region is extremelt dusty and dust streaks are ubiqutous.
I couldn't determine the slope of the hillside on which the avalanche occured from MOLA elevation data. The area in the portion of the CTX image shown in the article is very small (only about 2 X 2 km) and below the useful resolution of the gridded MOLA dataset from the JMars program. Maybe someone knows a more sophisticated way to determine the slope. In any case I would guess that 30 degrees or more of slope is certainly possible.
Tom
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Stu
post May 16 2010, 07:01 AM
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Anyone else having trouble opening up images with the IAS Viewer?


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JohnVV
post May 16 2010, 07:20 AM
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never used it till now.
it is crashing on Arch Linux Firefox 3.6.3
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Stu
post May 16 2010, 07:33 AM
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Thanks, John. Anyone else?


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nomisn
post May 16 2010, 08:15 AM
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Hi Stu

Just tried opening a HIRISE photo using IAS viewer from the HIRISE website and it didn't open ( I selected JP2 quicklook
IAS viewer) and got the following messages " Error in JPEG2000 Client unable to resolve host address "hijpip.lpl.arizona.edu"

and "unable to init IAS_TCPclient for server/port:hijpip.lpl.arizona.edu/8064"

Obviously something is up with IAS or the Hirise site at present
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Tman
post May 16 2010, 08:24 AM
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Yes, (here) it stops when the main window has opened and it has displayed sporadically a "Asynchronous Warning".


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Stu
post May 16 2010, 08:25 AM
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Thanks everyone who responded, appreciate it. So does my PC; it was *this* close to being hurled out the window... laugh.gif


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tharrison
post Jun 8 2010, 05:27 AM
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QUOTE (nprev @ May 11 2010, 07:14 AM) *
Interesting, but I dunno if I buy it. Why isn't there the usual dark ejecta apron around the postulated recent crater? Also, there's something not quite right about the diffuse upper boundary of the streak; that also seems atypical.


The dark areas seen around most new martian impact craters are not ejecta features, but rather blast zones. The impacts basically blow away the dust on the surrounding surface, making it appear dark compared to the adjacent dust-mantled surfaces.


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climber
post Jul 16 2010, 02:32 PM
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More beauties here: http://www.spaceflightnow.com/news/n1007/15hirise/


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Phil Stooke
post Jul 29 2010, 02:21 PM
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Somewhere recently we were discussing the possibility of using super-resolution with scanning cameras, specifically HiRISE. I did an experiment using pictures of the old Spirit lander. I tried finding images of other places at Meridiani - Beagle crater, Eagle crater... but the difficulty was finding multiple high quality images of the same location with comparable lighting and atmospheric conditions. Despite what you might think there are not many places where the coverage is OK for this. For instance, Opportunity can be illuminated from either the north or the south at different seasons, and that wrecks any chance of combining images effectively. If you compare the three raw images you can see how each one samples the target slightly differently.

Anyway, here's a composite of five images of the Spirit lander, compared with the three best images of the set (the other two are less satisfactory in image quality and lighting). I'm using the versions which are not map projected, but I have then had to do some work myself to register them reasonably well.

The composite was made by enlarging to 4x the original scale and registering, but without the addition of sharpening any layers. It shows some promise, I think, but the process would benefit from specially targeted images taken at the same season. Not very likely in my opinion!

Phil

Attached Image


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ElkGroveDan
post Jul 29 2010, 02:34 PM
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Thanks Phil. Here was your previous post.

This is a concept that fascinates me and I believe what you did here shows there is some promise to this. Long before I learned of the super-res application in digital images, I penciled out an analogous process for film photography that I never got around to experimenting with. I won't clutter up this discussion with it. Meanwhile I think I'm going to go try this with some distant horizon photos here on Earth.


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Stu
post Oct 6 2010, 08:24 PM
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Oooh, that's pretty...

Attached Image


(crop from ESP_018827_2640 )

Looks like a LOT of rock fell from the scarp face, slammed into the ground below, exposing some ice beneath the surface..?


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elakdawalla
post Oct 6 2010, 08:30 PM
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Although I'm not totally sure I agree with the ice part of the interpretation (because that spot in the fan should be an area of deposition, not exposure, if I'm seeing things correctly), that is a well spotted find!


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