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Zone 2 spans selenographic longitude 30°E to 50°E and contains
sights best observed two or three days after the new or full Moon.
KEY
Lunar 100 objects that have not yet been photographed.
Lunar 100 objects that have been photographed.
Other objects that have been photographed.
The Lunar 100 list is from "Introducing the Lunar 100" by Charles A. Wood (Sky & Telescope, Sky Publishing Corp., April 2004, Vol. 107, No. 4, pp. 113-120). All rights remain with Sky Publishing Corp. I (MSS) have transcribed this list for my personal use and any errors are mine.

Unless stated otherwise, all photographs will be oriented such that north is up and lunar west to the left.

12 Proclus Oblique-impact rays 16.1°N 46.8°E 28 km Rükl 26
lunar12

02:00 UTC January 7, 2006
1/8 sec - f4.9 - ISO 100
3.0× telephoto
25.0 mm eyepiece with barlow (291.8×)
This is an average of eight color and eight B&W images. Before combining the color with B&W, the red-green-blue components in the color image were aligned. After combination, the contrast enhanced slightly and an unsharp mask (3.0; 1.0; 0) was applied.

Proclus is the source of L12 (N18), its "oblique-impact rays". Note how the rays, the streaks of lighter material, radiate from Proclus to the north, east and south but not to the west. This implies something interesting happened here. The most likely cause is an asteroid striking at a very shallow, or oblique, angle from the southwest. But then why is the Proclus crater round and not elongated from the southwest to the northeast? Strangely enough, models indicate this is what should happen. The asteroid is moving so fast that the surface material at the point of impact can't get thrown out of the way. Instead, the energy of the impact heats the surface material which explodes outward creating a round crater. Only only on the periphery can the sufrace material be thrown out, preferentially "splashing" material away in the direction the asteroid was traveling.



25 Messier and Messier A Oblique ricochet-impact pair 1.9°S 47.6°E 11 km Rükl 48
lunar100 25

02:38 UTC April 1, 2004
1/4 sec - f4.9 - ISO 400
3.0× telephoto
12.5 mm eyepiece (300x)

Messier and Messier A are the small, white pair of craters, near the center of the picture, in Mare Foecunditatis with the pair of rays extending to the west-southwest. This is considered a ricochet-impact pair. The rays are brighter material lying under Mare Foecunditatis which was excavated by the impacts and preferentially scattered in one direction. And yes, these craters are named for Charles Messier, author of the famed Messier catalog of deep-sky objects.



40 Janssen Rille Rare example of a highland rille 45.4°S 39.3°E 199 km Rükl 67,68
58 Rheita Valley Basin secondary-crater chain 42.5°S 51.5°E 445 km Rükl 68
lunar100 40, 58

01:12 UTC April 15, 2005
1/15 sec - f4.9 - ISO 400
3.0× telephoto
12.0 mm eyepiece (312x)
This is an average of two images with an unsharp mask (5.0; 0.5; 0) applied.

Janssen Rille lies in Janssen crater. The illumination is not optimal here but one can just make out the valley extending northward and slightly west of the central peak of the crater, then looping back to the east towards the smaller overlapping crater, Fabricius.

To the northeast is Rheita Valley. Not a valley as we normally think of it, Rheita is actually believed to be a chain of closely spaced, overlapping craters.



96 Leibnitz Mountains Rim of South Pole-Aitken basin 85.0°S 30.0°E   Rükl 73,V
Leibnitz Mountains Leibnitz Mountains
04:33 UTC January 13, 2006
1/60 sec - f4.9 - ISO 100
3.0× telephoto
12.0 mm eyepiece (312x)
This is a combination of eight B&W photos. I enhanced the contrast and applied an unsharp mask (3.0; 1.0; 0.0) to each. I averaged the individual images and, again, applied an unsharp mask (3.0; 1.0; 0.0) and enhanced the contrast. The shadowing in the corners is vignetting. The camera is seeing to the edge of the eyepiece. Move the cursor over the image to see individual mountains labelled.

The name Leibnitz Mountains is not an officially sanctioned name but has been in common use for many years. The two peaks at the edge of the Moon's disk are designated M4 and M5 and are estimated to be 9,100 m (30,000 ft) in height. A little inward from the edge are two more peaks casting shadows towards the edge. These are M1 and M3 and are 4,600 and 7,600 m (15,000 and 25,000 ft) respectively. Some of this information comes from the Astrospider Lunar 100 entry on the Leibnitz Mountains by Mike Tyrrell and "Observing the Lunar Libration Zones" by Alexander Vandenbohede.

Last modified: 2009-04-25