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Post by Jairo on Jan 26, 2011 8:56:45 GMT -4
What causes the ground near Aldrin to be brighter in this picture? Is it a remnant of opposition effect, or is it light reflected from the suit or LM? Or is the ground actually different there? Thanks. |
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Post by gwiz on Jan 26, 2011 10:54:44 GMT -4
The sun is behind him, he's standing next to the LM, so both suit and LM will be reflecting light into that area.
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Bob B.
Bob the Excel Guru?
Posts: 3,072
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Post by Bob B. on Jan 26, 2011 12:15:15 GMT -4
The sun is behind him, he's standing next to the LM, so both suit and LM will be reflecting light into that area. Furthermore, that area is the ground the LM exhaust swept over during landing. This action modified the surface it that region, thus changing the optical properties. |
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Post by BertL on Jan 26, 2011 12:15:26 GMT -4
It also looks like that part of surface is angled differently; it might be inclined in a way it reflects more of the sunlight.
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Post by dwight on Jan 26, 2011 12:52:53 GMT -4
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Post by lukepemberton on Jan 26, 2011 14:41:21 GMT -4
All explained by Mr Windley at Clavius. If in doubt, give Clavius a clout. |
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Post by PhantomWolf on Jan 26, 2011 20:03:12 GMT -4
All explained by Mr Windley at Clavius. If in doubt, give Clavius a clout. The wikipedia image has been modified too. Other than being far darker, the image has been rotated, the bottom cropped and "sky" added to the top, and the fiducials have all been removed. |
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Post by gonetoplaid on Jan 27, 2011 14:03:42 GMT -4
What causes the ground near Aldrin to be brighter in this picture? Is it a remnant of opposition effect, or is it light reflected from the suit or LM? Or is the ground actually different there? Thanks. The Apollo 11 LM drifted a bit to the left just before touchdown. Thus the terrain immediately around and behind Aldrin was somewhat scoured smoother and more free of very fine dust, leaving both a smoother surface and a somewhat higher percentage of glass beads in the lunar regolith exposed to sunlight. Since the sun was behind and to the right of Aldrin, the result is that the ground now reflects light better towards the down-sun direction where Armstrong with the camera was standing. You might want to check out my analysis of photo AS11-40-5903 on my web site. Here is the link. Just scroll down to the photo. www.mem-tek.com/apollo/ISD.htmlI do have a typo on the page in the above link. The ISD scan was made from their Kodachrome contact duplicate negative of the original Ektachrome transparency film from the mission. My full web site for Apollo stuff is at: apollo.mem-tek.com/  |
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