September 30, 2004

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Crisium Closeup



Image Credit: Stefan Seip

Crisium Closeup

One of the most distinctive regions on the Moon is Mare Crisium, which is isolated from all other maria and visible even without binoculars. Mare Crisium, like Mare Humorum, has suffered few subsequent large impacts, and the lava is deep enough that only a few older craters stick through it. Chief among these are Yerkes and Lick, which formed on a shallow bench whose edge is marked by a roughly concentric ring of mare ridges. The basin rim of Crisium is unique in featuring squat mountains, called massifs. Perhaps the Apennines around Imbrium would look similar if the mare flooding was deeper. Just north of Crisium is one of the larger lunar craters that is widely unobserved. Cleomedes (diameter 126 km, depth 4.3 km) is often overlooked because the interesting features on its floor are hard to see. Stefan has taken one of the few images to clearly show the rille and a possible dome (arrowed on mouseover). I have enhanced the contrast and inserted an enlarged Cleomedes into the corner of Stefan's image. Because the Lunar Orbiter IV images of Cleomedes are poor, it is a great target for high resolution imaging!

Chuck Wood

Technical Details:
Aug 3, 2004, 2:54 UT. Astro-Physics 10" f/14.6 Maksutov-Cassegrain reflector @ f/30 (eff. focal length: 7400mm) + Astro-Physics 2x Barlow + SBIG STL 11000M camera; Exposure Time(s): 0.05 seconds; Dark- and flatframes applied; MaxIm DL, PhotoShop. This is not a mosaic nor a composite, but a single frame.

Related Links:
Lunar Orbiter IV View
Stefan's Astro-images

Yesterday's LPOD: Mountains at the Pole

Tomorrow's LPOD: Julius Franz and Mare Orientale

Author & Editor:
Charles A. Wood


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