Lat: 16.32°S, Long: 17.64°W, Diam: 48.73 km, Depth: 0.28 km, Rükl: 53
LOIV 120 H2 Opelt is the large partial ring at center. The fresh 8 km crater at 7 o'clock, accompanied by hills, is Opelt E.
- IAU page: Opelt
- Depth data from Kurt Fisher database
- Westfall, 2000: 0.28 km
- Satellite crater Opelt E is on the ALPO list of banded craters
- Named for Friedrich Wilhelm Opelt (1794-September 23, 1863) and his son Otto Moritz Opelt (1829-1912).
- Opelt is Catalog number 2852 in Mary Blagg's Collated List. She attributes the name to Julius Schmidt, and notes that the feature was not named in the works in Neison, 1876 or Beer and Mädler. Schmidt says on page 179 of his book that he intended to honor both of the men (F. W. and his son Moritz) who helped him prepare his 1878 edition of Lohrmann's 25-section map, however Who's Who in the Moon mentioned only the father, and hence only that attribution was included when the USGS prepared the initial version of the IAU Planetary Gazetteer.
- The name of O. M. Opelt was officially added to the IAU database on November 5, 2012, largely as a result of behind-the-scenes efforts by professional writer and amateur selenographer Robert Garfinkle.
- According to Who's Who in the Moon (1938), F. W. Opelt "was born in Rochlitz (Bavaria), became a successful financier in Saxony, and was private financial advisor to the State; he died in Dresden." In addition to assisting, along with his son, Julius Schmidt in editing Lohrmann's Mondkarte (Leipzig, 1878), "he also translated into German, with notes and additions, Francoeur’s Traité élémentaire de Mécanique." Moritz Opelt was separately the author of a rare lunar observer's handbook, Der Mond: Populäre Darstellung der Verhältuisse und Ercheinungen welche von diesem Weltkörper bekaunt sind (1879).
- It appears that F. W. Opelt was a friend of Lohrmann who helped him with the mathematical reduction to selenographic longitude and latitude of his micrometrical measurements of the positions of about 50 lunar craters and peaks using the methods of Encke. He also supervised the preparation of engravings from Lohrmann's drawings after Lohrmann's death. Five of the measurements were apparently repeated by the elder Opelt's son.
- As noticed by Danny Caes, the IAU's Named Lunar Formations has a footnote on page 107 stating that Krieger proposed the name Keeler (now used for a farside crater) for this feature.
- Opelt, O. M. 1879. Der Mond -- book with 40 cm map, and skeleton map with names and heights