Crisium Closeup
Explanation:
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
