Helicon (crater)

Helicon is a small lunar impact crater that is located on the north part of the Mare Imbrium. The crater was named after 4th century BC Greek astronomer Helicon of Cyzicus,[1] a friend and disciple of Plato.[2] To the northwest is the prominent Sinus Iridum, a mountain-ringed bay on the mare. Just to the east is the slightly smaller crater Le Verrier.

Helicon

Lunar Orbiter 4 image
Coordinates	40.4°N 23.1°W / 40.4; -23.1
Diameter	25 km
Depth	0.5 km
Colongitude	23° at sunrise
Eponym	Helicon

Highly oblique view of Helicon (left) and Le Verrier (right). The mountain on the horizon at left is Promontorium Laplace, about 180 km beyond Helicon. Note that Helicon's ejecta is buried by the mare lava, but Le Verrier's is not. From Apollo 15.

Another oblique view of Helicon (left), at a higher sun angle. Also from Apollo 15.

Helicon is a nearly circular formation with inner walls that curve down to a relatively flat floor. There is a tiny craterlet located at the midpoint of the interior, and a small craterlet along the southwestern rim.

Satellite craters

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

Helicon	Latitude	Longitude	Diameter
B	38.0° N	21.3° W	6 km
C	40.1° N	26.2° W	1 km
E	40.5° N	24.1° W	3 km
G	41.7° N	24.9° W	2 km

References

1. "Helicon (crater)". Gazetteer of Planetary Nomenclature. USGS Astrogeology Research Program.
2.  This article incorporates text from a publication now in the public domain: Mason, Charles Peter (1870). "Helicon". In Smith, William (ed.). Dictionary of Greek and Roman Biography and Mythology. 2. p. 372.

• Andersson, L. E.; Whitaker, E. A. (1982). NASA Catalogue of Lunar Nomenclature. NASA RP-1097.CS1 maint: ref=harv (link)
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• Price, Fred W. (1988). The Moon Observer's Handbook. Cambridge University Press. ISBN 978-0-521-33500-3.CS1 maint: ref=harv (link)
• Rükl, Antonín (1990). Atlas of the Moon. Kalmbach Books. ISBN 978-0-913135-17-4.CS1 maint: ref=harv (link)
• Webb, Rev. T. W. (1962). Celestial Objects for Common Telescopes (6th revised ed.). Dover. ISBN 978-0-486-20917-3.CS1 maint: ref=harv (link)
• Whitaker, Ewen A. (1999). Mapping and Naming the Moon. Cambridge University Press. ISBN 978-0-521-62248-6.CS1 maint: ref=harv (link)
• Wlasuk, Peter T. (2000). Observing the Moon. Springer. ISBN 978-1-85233-193-1.CS1 maint: ref=harv (link)

External links

• Wood, Chuck (2006-08-20). "Out the Porthole". Lunar Photo of the Day. Retrieved 2016-09-18., excellent earth-based image of Sinus Iridum and vicinity, including Helicon and Le Verrier