Alphonsus (crater)

Alphonsus
LRO image
Coordinates13°23′S 2°51′W / 13.39°S 2.85°W / -13.39; -2.85
Diameter110.54 km
Depth2.7 km
Colongitude4° at sunrise
EponymAlfonso X
The crater area in a Selenochromatic format Image (Si)
Alphonsus crater appears in the right half of this image taken by Ranger 7. NASA photo.

Alphonsus is an ancient impact crater on the Moon that dates from the pre-Nectarian era.[1] (Older sources state that it is Nectarian in age.[2]) It is located on the lunar highlands on the eastern end of Mare Nubium, west of the Imbrian Highlands, and slightly overlaps the crater Ptolemaeus to the north. To the southwest is the smaller Alpetragius. The crater name was approved by the IAU in 1935.[3]

  1. ^ Ambrose, W.A. "ORIGIN, DISTRIBUTION, AND CHRONOSTRATIGRAPHY OF ASYMMETRIC SECONDARY CRATERS ASSOCIATED WITH NEARSIDE LUNAR BASINS" (PDF). Bureau of Economic Geology. University of Texas at Austin, TX. Retrieved 25 September 2013.
  2. ^ The geologic history of the Moon. USGS Professional Paper 1348. By Don E. Wilhelms, John F. McCauley, and Newell J. Trask. U.S. Government Printing Office, Washington: 1987. Table 9-4.
  3. ^ Alphonsus, Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)