Woltjer is an
impact crater
An impact crater is a depression (geology), depression in the surface of a solid astronomical body formed by the hypervelocity impact event, impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal c ...
that is located in the northern
latitude
In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...
s of the
Moon
The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...
's
far side. It is just attached to the southern outer rim of the larger crater
Montgolfier
The Montgolfier brothers – Joseph-Michel Montgolfier (; 26 August 1740 – 26 June 1810) and Jacques-Étienne Montgolfier (; 6 January 1745 – 2 August 1799) – were aviation pioneers, balloonists and paper manufacturers from the Communes o ...
. To the southwest is
Schneller and to the east is
Stoletov. It is named after astronomer
Jan Woltjer.
This is a relatively recent impact compared to most of the craters on the far side, and the rim is still well-formed with little erosion. It is old enough, however, that its
albedo
Albedo ( ; ) is the fraction of sunlight that is Diffuse reflection, diffusely reflected by a body. It is measured on a scale from 0 (corresponding to a black body that absorbs all incident radiation) to 1 (corresponding to a body that reflects ...
matches its surroundings and it lacks a
ray system
In planetary geology, a ray system comprises radial streaks of fine '' ejecta'' thrown out during the formation of an impact crater, looking somewhat like many thin spokes coming from the hub of a wheel. The rays may extend for lengths up to ...
. The inner wall has slumped in places and formed piles of
talus along the south. The interior floor has two lines of low ridges that begin in the southeast and curve up to the northwestern inner wall. There is a level patch in the southern floor near the inner wall.
The crater was formally named by the
IAU
The International Astronomical Union (IAU; , UAI) is an international non-governmental organization (INGO) with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach, education, and developmen ...
in 1970 after Dutch astronomer
Jan Woltjer.
Woltjer
Gazetteer of Planetary Nomenclature, International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
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 Woltjer.
References
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External links
{{commons category-inline, Woltjer (lunar crater)
Lunar Orbiter Photo Number V-039-H3
Impact craters on the Moon