Journey to Mt Sharp - Part 4: Beyond the Kimberley, Sol 634 [May 19, '14] to 706 [Jul 31, '14] |
Journey to Mt Sharp - Part 4: Beyond the Kimberley, Sol 634 [May 19, '14] to 706 [Jul 31, '14] |
May 19 2014, 07:00 PM
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#1
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
I'd say that the sol 634 drive put the Kimberley in the rear-view mirror, so it's time for a new thread! Let's see how fast they can move toward Murray Buttes now!
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May 23 2014, 06:06 PM
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#2
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Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
Floyd: roughly I get that the rock is 14.5 meters away and covers an angle of about 8.1 degrees in the NAVCAM frame. That would make it about 2 meters across at the base.
EDIT: I got the distance estimate using 38 pixels of shift in position between NAVCAM L and R, baseline of .414m: d=(.414/2)/tan(45.33/1024*38/2) -- Fred's estimate using the map could be closer, who knows. -------------------- |
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May 24 2014, 05:41 AM
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#3
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Senior Member Group: Members Posts: 4250 Joined: 17-January 05 Member No.: 152 |
Floyd: roughly I get that the rock is 14.5 meters away and covers an angle of about 8.1 degrees in the NAVCAM frame. That would make it about 2 meters across at the base. EDIT: I got the distance estimate using 38 pixels of shift in position between NAVCAM L and R, baseline of .414m: d=(.414/2)/tan(45.33/1024*38/2) -- Fred's estimate using the map could be closer, who knows. OK, I checked and got similar numbers using parallax: 13.8 +/- 0.5 metres, and 39.5 +/- 3 metres for the farther rock. I used a navcam separation of 42.4 cm from "The Mars Science Laboratory Engineering Cameras", Maki etal. If these numbers are correct, you should shrink the men by around 10-15% in my image. Either way these are big rocks. |
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May 24 2014, 11:01 AM
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#4
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Senior Member Group: Members Posts: 1465 Joined: 9-February 04 From: Columbus OH USA Member No.: 13 |
Either way these are big rocks. That's the bottom line--without a reference appearances are often deceiving, but not in this case. BTW, my calculation above getting the parallax by counting pixels of offset between L and R doesn't take into account any possible toe-in or -out of the respective optical axes. -------------------- |
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May 24 2014, 10:44 PM
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#5
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Senior Member Group: Members Posts: 4250 Joined: 17-January 05 Member No.: 152 |
my calculation above getting the parallax by counting pixels of offset between L and R doesn't take into account any possible toe-in or -out of the respective optical axes. I took that into accound, as well as 0.35 degrees of relative field rotation between L and R. (I just aligned the L and R frames until the distant slopes coincided.) But I didn't use the proper pixel scale - I just assumed 45 degrees/1024 pixels, when it actually varies quite a bit across the field. The reference I cited above gives a pixel scale of 0.82 mrad/pixel at the centre of the frame, which is where the near rock is. That gives a distance of 12.9 +/- 0.5 metres, which now is pretty much consistent with the estimate from Phil's map. |
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