Alexander (crater)
 Lunar Orbiter 4 image (spots are blemishes on original image) | |
| Coordinates | 40°18′N 13°30′E / 40.3°N 13.5°E |
|---|---|
| Diameter | 94.80[1] km |
| Depth | 410[2] m |
| Colongitude | 347° at sunrise |
| Formation | pre-Imbrian[2] |
| Eponym | Alexander the Great |
Alexander is a lunar impact crater-like feature in the rugged surface to the north of Mare Serenitatis.[3] This depression dates to the pre-Imbrian epoch, while the mare-covered floor is from the Imbrian period.[2] Alexander lies to the south-southwest of the prominent crater Eudoxus, and to the east-northeast of Calippus.
If this ever was an impact crater,[4] the Alexander formation has been so heavily worn and distorted with the passage of time that it now resembles little more than a lowland region enclosed by rugged ranges. The rim segments lie along the northwest, west, and south sections of the depression, while the eastern side stands open to the surrounding surface. The surviving walls are nearly rectangular in form, with the most prominent mounts in the northwest.
The floor is more smooth and has a darker albedo in the western half, and gradually grows lighter and more impacted toward the east. It has a number of small hills. There are no craters of significance within the perimeter of this formation, although there are tiny craterlets aplenty in the rougher eastern section.[5]: 26 The infrared spectrum of pure crystalline plagioclase has been identified on the east rim.[6]
This depression was named after Alexander the Great (356 – 323 BC). Its designation was formally adopted by the International Astronomical Union in 1935.[1] The name was introduced into lunar nomenclature by amateur selenographers William R. Birt and John Lee in the nineteenth century.[7]
Satellite craters
[edit]By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Alexander.[8]
| Alexander[5]: 291 | Latitude | Longitude | Diameter |
|---|---|---|---|
| A | 40.7° N | 14.9° E | 4 km |
| B | 40.3° N | 15.2° E | 4 km |
| C | 38.5° N | 14.9° E | 5 km |
| K | 40.5° N | 19.3° E | 4 km |
References
[edit]- 1 2 "Alexander". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
- 1 2 3 Westfall, John E. (2000). Atlas of the Lunar Terminator. Cambridge University Press. p. 202. ISBN 978-0-521-59002-0.
- ↑ Moore, Patrick (2001). On the Moon. Sterling Publishing Co. pp. 171–172. ISBN 978-0-304-35469-6. Retrieved 2026-05-10.
- ↑ Wood, Charles A. (June 19, 2006). "Not a Crater?". Lunar Photo of the Day. Retrieved 2026-05-10.
- 1 2 Bussey, B.; Spudis, P. (2004). The Clementine Atlas of the Moon. New York: Cambridge University Press. p. 291. ISBN 978-0-521-81528-4.
- ↑ Donaldson Hanna, K. L.; et al. (July 2014). "Global assessment of pure crystalline plagioclase across the Moon and implications for the evolution of the primary crust". Journal of Geophysical Research: Planets. 119 (7): 1516–1545. Bibcode:2014JGRE..119.1516D. doi:10.1002/2013JE004476.
- ↑ Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. p. 221. ISBN 978-0-521-62248-6.
- ↑ Grego, P. (2015). "Satellite Crater". In Hargitai, H.; Kereszturi, Á. (eds.). Encyclopedia of Planetary Landforms. New York, NY: Springer. doi:10.1007/978-1-4614-3134-3_328.
Sources
[edit]- 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. Reprint: ISBN 978-0-486-20917-3
- Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.
| Physical properties |  | |
|---|---|---|
| Orbit | ||
| Surface and features | ||
| Science | ||
| Exploration | ||
| Time-telling and navigation | ||
| Phases and names | ||
| Daily phenomena | ||
| Related |
| |
