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HiRise Imagery of Opportunity's trek, ...or, a blast from the past
Guest_Sunspot_*
post Dec 4 2006, 11:02 PM
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Is anyone else really surprised at just how much more detail MRO has? There was some debate prior to MRO arriving as to whether it would be drastically different to MGS, but every time I see a direct comparison of scenes taken by both cameras i'm stunned. .

I posted this a while ago:
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elakdawalla
post Dec 4 2006, 11:05 PM
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New HiRISE release includes a third view of Opportunity! Talk about being able to locate the rover's trek precisely...

http://hiroc.lpl.arizona.edu//images/PSP/opportunity.html
http://hiroc.lpl.arizona.edu//images/PSP/O...-step-movie.jpg

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stevesliva
post Dec 4 2006, 11:48 PM
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QUOTE (Sunspot @ Dec 4 2006, 06:02 PM) *
Is anyone else really surprised at just how much more detail MRO has? There was some debate prior to MRO arriving as to whether it would be drastically different to MGS, but every time I see a direct comparison of scenes taken by both cameras i'm stunned.

Yes, me too. They tell me it's not just resolution, but a signal-to-noise improvement. Amazing regardless.
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djellison
post Dec 4 2006, 11:56 PM
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Bouncey bouncey....

Ties in well with
http://photojournal.jpl.nasa.gov/jpeg/PIA05225.jpg


Doug
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elakdawalla
post Dec 5 2006, 12:06 AM
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Neato! Well spotted, Doug! biggrin.gif

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CosmicRocker
post Dec 5 2006, 06:32 AM
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Excellent! How did some of us miss the bounces? wink.gif What else is hiding in it?

The HiRise people have been busy lately, haven't they? The most recently released images are rightly stealing the show, but the caption from the Victoria anaglyph released today contained some useful information for the vertical exaggeration in stereo discussion. I think they provided the viewing angles for the first two passes over Victoria, which allow us to more accurately calculate the baseline from MRO's viewpoint, using Doug's estimation of the average vertical height of the passes.

The angular separation between the views appears to be closer to 12 degrees, according to
http://hiroc.lpl.arizona.edu//images/PSP/victoria.html

Using simple geometry with the new angles, I calculate about 61 km for the baseline. Using 20 degrees, I essentially get the same number Doug did. Using the formula from the site I linked to earlier and this new data, I calculate a vertical exaggeration for the Victoria stereo as about 1.44 for someone with eyes spaced 7 cm apart and viewing the anaglyph from 18 inches (roughly 45 cm) from their monitor. If that person moved his/her eyes to about 12 inches from the screen, the vertical exaggeration should be around 1:1. Viewing it from 24 inches from the screen should result in a 2:1 vertical exaggeration, etc...

I've created an Excel spreadsheet that can be used to play "what if" games with the variables. I tried to make it somewhat friendly for people who might not be familiar with Excel spreadsheets, so others could experiment with the variables. It can be easily modified for use with other stereo pairs, if you are familiar with spreadsheets. I have tested it enough to convince myself that it seems to agree qualitatively with what I see when viewing this pair of images. If anyone detects errors in it, please make me aware of them. I have been known to screw up. wink.gif
Attached File  Vertical_Exaggeration_from_aerial_imagery.xls ( 36K ) Number of downloads: 425


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Guest_Oersted_*
post Dec 5 2006, 01:40 PM
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QUOTE (djellison @ Dec 4 2006, 11:47 PM) *
The backshell is really getting my attention. The immediate thought from MOC was that the backshell was on the left with the parachute to the right. What appeared to be the parachute it now seems was just the surface disturbance from a very high speed impact of the backshell.....let the gif load for a while, it shows both.


It can be seen that the backshell hit at the rightmost point in the picture, and then skidded/bounced to its final resting place a bit to the left of initial impact. The general bright splotch in the MOC image that encompasses both parachute and backshell fits well with a spray of sand ejected in the first impact of the backshell. Notice how the light-coloured area begins at impact point and then radiates leftward from that point. Now, years later, the colour of the general area is back to the uniform surface colour due to the wind. As with the airbag bounce marks, a light colour indicates a disturbance in the top layer, exposing lower material. At least, that's how I see it. Other opinions?
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djellison
post Dec 5 2006, 01:51 PM
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I think you have it about right - the challenge is now to try and figure out the config. of the backshell on the surface - see how broken it actually is....and that isn't easy smile.gif

Maybe they could abandon Victoria and just nip back to check it out.....

ph34r.gif

tongue.gif

Doug
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RobertEB
post Dec 5 2006, 02:29 PM
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Too bad they didn't have these pictures when Opportunity was fighting its way through the dunes.


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ElkGroveDan
post Dec 5 2006, 04:32 PM
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QUOTE (djellison @ Dec 4 2006, 03:56 PM) *
Bouncey bouncey....

Look at the third bounce in that image. It catches the edge of a very small crater which then deflects the direction of motion off to the left a bit..just enough to put her down in Eagle. In makes me think that if that first bounce had been just a half meter farther south, it would have missed that little crater and bounced on up to the northeast of Eagle Crater, missing it entirely.


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Ant103
post Dec 5 2006, 05:04 PM
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It's like a "giant golf" after all biggrin.gif
JPL had realize a very good swing.


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djellison
post Dec 5 2006, 05:22 PM
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QUOTE (ElkGroveDan @ Dec 5 2006, 04:32 PM) *
It catches the edge of a very small crater


Yup - not quite visible in this but you are right...

http://photojournal.jpl.nasa.gov/jpeg/PIA05227.jpg

I've looked for bounces at Gusev....no luck ( maybe the first, but none after that )

Doug
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climber
post Dec 5 2006, 05:36 PM
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QUOTE (djellison @ Dec 5 2006, 06:22 PM) *
Yup - not quite visible in this but you are right...

...while Bounce rock doesn't seam to have diverted the trajectory.
Did you notice the 2 whitish spots close to Eagle?
I've tried to find Bounce Rock assuming it was 28 m from the center of Eagle. Frankly I have other candidates but this is an attempt to locate it. May be easier in the raw image. In the absolute, as we've seen Adirondack, BR may be visible too.
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QUOTE (djellison @ Dec 5 2006, 06:22 PM) *
I've looked for bounces at Gusev....no luck ( maybe the first, but none after that )

As I said in Spirit topic, the albedo difference in Sleeping Hollow was quite big seen from Spirit position just after landing. Strange we see nothing there.
What would be interesting too, would be to try to match the DD path of known DD with MRO picture.


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fredk
post Dec 5 2006, 06:29 PM
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It's an impressive attempt at identifying the bounces Doug, but I have to say looking at the original full-scale image, even with considerable stretching, that only perhaps a few of your identified bounces are convincing. There are many other similar vague lightish smudges in the vicinity. It may just be that almost three years of dust deposition has rendered the bounce marks indistinguishable from the background.
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djellison
post Dec 5 2006, 08:50 PM
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QUOTE (fredk @ Dec 5 2006, 06:29 PM) *
There are many other similar vague lightish smudges in the vicinity..


Yes - but not on the actual trajectory as dictated by IMU data and matching the bounces as seen in the reconstruction of that data smile.gif

Doug
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