Ammonius is a bowl-shaped
lunarimpact crater with a slightly raised rim. It is located on the floor of the walled plain
Ptolemaeus, about 30 kilometers northeast of the crater midpoint.
Just to the north on the
lava-flooded floor of Ptolemaeus is a relatively prominent
"ghost" crater: the discernible buried rim of a pre-existing crater. The diameter of this ghost crater is nearly double that of Ammonius, and is currently identified as Ptolemaeus B.
Names
The crater is named after Greek philosopher
Ammonius Hermiae.[1] In the past this crater was identified as Ptolemaeus A, before being named by the
IAU in 1976.
References
^"Ammonius (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
Andersson, L. E.;
Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.
Menzel, D. H.; Minnaert, M.; Levin, B.; Dollfus, A.; Bell, B. (1971). "Report on Lunar Nomenclature by the Working Group of Commission 17 of the IAU". Space Science Reviews. 12 (2): 136–186.
Bibcode:
1971SSRv...12..136M.
doi:
10.1007/BF00171763.
S2CID122125855.