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37 - Aristoteles - Stereo | by jimmosher
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37 - Aristoteles - Stereo

This is a stereo composite of two Lunar Orbiter IV images showing the region around the 87-km diam crater Aristoteles, based on images IV-103-H and IV-104-H from the USGS Lunar Orbiter Digitization Project website. This region was discussed in the Lunar Picture of the Day (LPOD) for Sept. 11, 2007.


The freeware Lunar Terminator Visualization Tool was used to map the LO images into identical aerial views. The deviations between the two images show the misregistrations that arise when features at different heights above the lunar surface are viewed at different angles. When viewed in stereo, our eye sees these differences as a vertical relief pattern.


North is approximately to the right, and east is down in this stereo view. The 30-km diameter crater Mitchell is below Aristoteles and overlapped by it. The 5-km crater at the top is Egede C, and 6-km Mitchell B can be seen almost touching the left margin (opposite the region of overlap between Aristoteles and Mitchell). In the area where Aristoteles and Mitchell overlap, two arcs can be seen in the inner wall of Aristoteles. They seem to correspond in both height and position to where one might expect an imaginary extension of the north and south walls of Mitchell to fall. The LPOD called particular attention to the more prominent westerly arc (the upper one in this view), which reveals its back-slope by casting a shadow when the Sun is low in the west (opposite to these views). The less prominent arc closer to the raised rim of Aristoteles seems a more likely extension of the shape of Mitchell. Other slumped terraces with backslopes (presumably unrelated to Mitchell) can be seen elsewhere in the frame, in particular to the north of the LPOD arc, and on the opposite rim, where the smaller of two slumped blocks seems to have a backwards slope on the side closest to the rim. That area shows as a bright ribbon of light in the LPOD photo, but the presence of sunlight proves only it is sloped by less than the local sun angle, not that it actually slopes down to the west. The stereo image makes it appear it does slope down on the side closest to the rim.


The individual frames from which is stereo view was constructed are shown at: (left)


and (right)


The regions where there was no overlap between the two photos has been colored in black.


To see the three dimensional effect, the present image requires viewing with special stereo glasses (red filter for left eye and blue filter for right eye).


It is also possible to see the 3D effect by downloading and viewing the separate left and right-eye images using a variety of other techniques.



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Uploaded on September 11, 2007