June 21, 2004

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Re-Projecting the Moon


Image Credit: J-P Metsavainio

Re-Projecting the Moon

Because the Moon is a sphere all features away from the sub-Earth point are seen with distortion that becomes progressively more extreme as the limb is approached. Circular craters look more and more elliptical until, at the limb they are seen in profile. This perspective effect makes studies of the limb difficult, and although Lunar Orbiter 4 and Clementine have provided overhead views of nearly the entire Moon, sometimes telescopic images can reveal features not seen on the existing space images. Now Finnish lunar observer J-P Metsavainio has used the power of commercial software to undistort limb regions. I hope others will experiment with J-P's technique. In addition to exploring the limbs, you can center images over Imbrium to try your own mapping of that basin's rings. Or center on Crisium to see its real shape, or on Nectaris to appreciate its extensive system of radial features, or on Schiller to convince yourself of the reality of that multi-ring basin. There is new life in your old lunar images!

Technical Details:
The original image was acquired Feb 28, 2004 using a Meade LX200 GPS 12" telescope and a Logitech 4000pro WebCam at prime focus. Fifty-two, 30 second AVI clips were stacked in RegiStax2 and the image was mosaicked in PhotoShop. Then J-P "used PhotoShop's 3D-transform filter to rotate the 2D-image of Moon. With this 3D-transform filter it was possible to "uncompress" the image data in the edges of the image and see more details. This method gives you feeling, that you can select you viewpoint freely from space!!!" This image was taken at Oulu, Finland, 65"N 25"35'E in the dead of winter with a huge amount of heat turbulence rising from buildings. The temperature was -22C!

Related Links:
Rectified Lunar Atlas

Yesterday's LPOD: Discover the Moon

Tomorrow's LPOD: A Fundamental Relation

Author & Editor:
Charles A. Wood



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