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Venus Full Disk -mariner 10
Bjorn Jonsson
post Sep 19 2005, 12:07 AM
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Interesting paper - I had forgotten the Mariner 10 pixels weren't square, reflecting the fact that I haven't done much work on the Mariner 10 images I have on my computer (I downloaded all of them several months ago).

The reseau marks probably form approximately straight, horizontal and vertical 'lines' in undistorted images. They do in the Voyager images which have a significant amount of distortion.

The attached image is a corrected (undistorted) Voyager image where the curved image edges are indicative of the distortion present in uncorrected images.

BTW I might have the positions of the reseau marks in undistorted Mariner 10 images somewhere on my computers (there are three of them wink.gif ) - I'm not sure though. I'll see if I can find them later this week.

And awesome mosaics - by far the best Mariner 10 Venus images I have ever seen.
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Malmer
post Sep 19 2005, 09:26 AM
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I would like to thank all of you for your kind comments!

I hope that I can continue to supply you all with images of the same quality. Im going trough the EDR archives for all the old missions because I think there are amazing treasures in there that most people have never seen. Most of the nasa releases are just single edr frames. Especially the older missions have very little high resolution material released. Probably due to the relative computer intensive nature of producing such images.

Im working ferociously with the mariner edr:s now. There are beautiful images of the earth and moon that i just need to composite. Im not sure if they will be in color but hopefully...

Right now im working on a lookup table for the mariner 10 edr:s that will linearize the pictures. I found images of the moon that have different exposures. I will make a text file that you all can use as soon as its finished. (and a photoshop curve if you would like that)

Does anyone have any information on viewing geometry? Right now im just using limb curvature and surface features to reverse engineer the spacecraft path. I need to write some code to speed this up a bit... Right now im doing it all "by hand" in 3dsMAX. (it works but takes forever, i did this for my enceladus images.)


Mattias
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edstrick
post Sep 19 2005, 10:45 AM
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I'm not sure but I think the Mariner 10 Earth/Moon pics were partly accidental. On launch, the camera lens heaters failed to turn on. They expected the cameras to defocus like the Deep Impact camera ended up as the lens barrels cooled down. They immediately fired up the imaging system for test and calibration pics, including a star cluster <Pleiades???>. Cameras stayed in focus just fine. Go Figure!

They had a backup spacecraft....they'd preped the engineering-test spacecraft for a contingency flight and had a spare atlas-centaur at the pad, and they wanted to know if the mission was going to lose imaging to defocused images in time to prep and launch in the launch window. It was fine and the vehicle ended up museumed. <new verb>
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Bjorn Jonsson
post Sep 19 2005, 11:12 AM
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QUOTE (Malmer @ Sep 19 2005, 09:26 AM)
Does anyone have any information on viewing geometry? Right now im just using limb curvature and surface features to reverse engineer the spacecraft path. I need to write some code to speed this up a bit... Right now im doing it all "by hand" in 3dsMAX. (it works but takes forever, i did this for my enceladus images.)

There might be SPICE kernels somewhere out there but you would probably still need to at least partially reverse engineer the viewing geometry. I had to do so when I did my global cylindrical map of Jupiter based on Voyager 2 images despite having some SPICE kernels and I doubt Mariner 10 is easier to deal with - it is after all even older than the Voyagers. The information on Voyager 2's location seemed rather accurate but the camera angles were way off (sometimes by more than 0.1 degrees). Also the north azimuth wasn't accurate - a problem also present in something far more modern: In the Cassini PDS data where there really are only two cases: (1) Extremely accurate north azimuth or (2) Garbage (north azimuth off by tens of degrees, i.e. no cases where it is off by a degree or two). This is annoyingly common.
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Malmer
post Sep 19 2005, 12:39 PM
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QUOTE (Bjorn Jonsson @ Sep 19 2005, 01:12 PM)
There might be SPICE kernels somewhere out there but you would probably still need to at least partially reverse engineer the viewing geometry. I had to do so when I did my global cylindrical map of Jupiter based on Voyager 2 images despite having some SPICE kernels and I doubt Mariner 10 is easier to deal with - it is after all even older than the Voyagers. The information on Voyager 2's location seemed rather accurate but the camera angles were way off (sometimes by more than 0.1 degrees). Also the north azimuth wasn't accurate - a problem also present in something far more modern: In the Cassini PDS data where there really are only two cases: (1) Extremely accurate north azimuth or (2) Garbage (north azimuth off by tens of degrees, i.e. no cases where it is off by a degree or two). This is annoyingly common.
*



Its relatively easy to reconstruct camera angles. Position is harder to reconstruct to the same exactnes. If i knew spacecraft positions in respect to the planet i would be happy. (3 degrees of freedom instead of 6 makes everything much easier)

I know how to reconstruct camera position/orientation from images because thats a very common problem in the special effects buissines (I am a 3d/2d artist by profession) but Im relatively new to the lingo used to discribe spacecraft position/orientation. Im not really sure on how to decipher words like "subspacecraft latitude","north azimuth", "right acension" and the like into something i can understand.

Where can i find these SPICE kernels?

/Mattais
*waving his newbie flag*
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ljk4-1
post Sep 19 2005, 02:34 PM
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QUOTE (edstrick @ Sep 19 2005, 05:45 AM)
I'm not sure but I think the Mariner 10 Earth/Moon pics were partly accidental.  On launch, the camera lens heaters failed to turn on.  They expected the cameras to defocus like the Deep Impact camera ended up as the lens barrels cooled down.  They immediately fired up the imaging system for test and calibration pics, including a star cluster <Pleiades???>.  Cameras stayed in focus just fine.  Go Figure!

They had a backup spacecraft....they'd preped the engineering-test spacecraft for a contingency flight and had a spare atlas-centaur at the pad, and they wanted to know if the mission was going to lose imaging to defocused images in time to prep and launch in the launch window.  It was fine and the vehicle ended up museumed.  <new verb>
*


Playing the What If game of alternate space exploration history: If they had launched Mariner 11, would it have been able to image the other side of Mercury that Mariner 10 had missed - three times?

And why didn't they launch it? Budgetary reasons?


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tedstryk
post Sep 19 2005, 04:24 PM
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QUOTE (ljk4-1 @ Sep 19 2005, 02:34 PM)
Playing the What If game of alternate space exploration history:  If they had launched Mariner 11, would it have been able to image the other side of Mercury that Mariner 10 had missed - three times?

And why didn't they launch it?  Budgetary reasons?
*



That is a good question. given the three rotations for every two orbits, I don't see why such a mission couldn't have been launched, but I could be wrong. Also, keep in mind that Mariner 10 was only supposed to be a one-flyby mission.


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