Firmicus (crater)

Firmicus

The Firmicus crater as seen from the Apollo 17 CSM
Coordinates	7.3°N 63.4°E / 7.3; 63.4
Diameter	56 km
Depth	1.5 km
Colongitude	297° at sunrise
Eponym	Julius Firmicus Maternus

Firmicus is a lunar impact crater that lies in the eastern part of the Moon's near side, so that from Earth it appears oval in shape due to foreshortening. It is, however, very nearly circular. The crater is located to the west of the Mare Undarum, and northeast of the similar-sized crater Apollonius. To the north of Firmicus are the craters van Albada and Auzout. Attached to its northwest rim is the Lacus Perseverantiae, a miniature lunar mare.

The crater is named after 4th century Roman astrologer Julius Firmicus Maternus. The name was formally adopted by the IAU in 1935.

The most notable aspect of Firmicus is the dark, flat floor. It has a similar albedo to the surface of Mare Crisium to the north, making it stand out somewhat from its surroundings. The floor has suffered no significant impacts since it was created, although there are undoubtedly many minor impacts across its surface. The outer rim of Firmicus has undergone some erosion, particularly along the northern rim where it is overlain by a pair of small craterlets.

Satellite craters

Firmicus crater and its satellite craters taken from Earth in 2012 at the University of Hertfordshire's Bayfordbury Observatory with the telescopes Meade LX200 14" and Lumenera Skynyx 2-1

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Firmicus.

Oblique view from Apollo 10, with Firmicus in the background and Mare Undarum in the foreground

Oblique view of Firmicus facing south from Apollo 17

Firmicus	Latitude	Longitude	Diameter
A	6.4° N	65.1° E	8 km
B	7.3° N	65.8° E	14 km
C	7.7° N	66.5° E	13 km
D	5.9° N	64.4° E	11 km
E	8.0° N	63.6° E	9 km
F	6.5° N	61.8° E	9 km
G	6.9° N	61.9° E	9 km
H	7.5° N	60.3° E	7 km
M	4.1° N	67.2° E	42 km

• 
  Firmicus C is a concentric crater
• 
  Oblique view of Firmicus C from Apollo 17

References

• Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.
• Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. ISBN 978-0-521-81528-4.
• Cocks, Elijah E.; Cocks, Josiah C. (1995). Who's Who on the Moon: A Biographical Dictionary of Lunar Nomenclature. Tudor Publishers. ISBN 978-0-936389-27-1.
• McDowell, Jonathan (July 15, 2007). "Lunar Nomenclature". Jonathan's Space Report. Retrieved 2007-10-24.
• 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. S2CID 122125855.
• Moore, Patrick (2001). On the Moon. Sterling Publishing Co. ISBN 978-0-304-35469-6.
• Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3.
• Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4.
• Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. ISBN 978-0-486-20917-3.
• Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6.
• Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.

External links

• LTO-62C1 Firmicus — L&PI topographic map