Northeastern Secchi at low sun angle, from Apollo 11
Secchi is a small lunarimpact crater formation on the northwest edge of Mare Fecunditatis. It was named after the 19th-century Italian astronomer Angelo Secchi.[1] To the northeast is the crater Taruntius. The western rim is joined with a section of the minor Montes Secchi range. The rim of this crater has been opened in the northern and southern ends, leaving two curved ridges facing each other across the crater floor. To the south is a pair of rilles designated the Rimae Secchi. These lie near the edge of the mare, and have a combined length of about 40 kilometers.
Satellite craters
By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Secchi.
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 Reviews12 (2): 136–186. doi:10.1007/BF00171763. Bibcode: 1971SSRv...12..136M.