Reiner Gamma

Lat: 7.39°N, Long: 58.96°W, Diam: 73.44 km, Depth: 0 km, Rükl: 28

Clementine -- by Paolo Amoroso

Images

Frame 2215, made by Lunar Orbiter 2, shows Reiner Gamma and its northeastern extension toward the Marius hills. Looking north.
A larger (and somewhat darker) scan of Lunar Orbiter 4's frame 157-h1 (LO4-157-h1) shows a much more detailed view of Reiner Gamma's peculiar appearance.
The upper right corner of Lunar Orbiter 4's frame 162-h1 (LO4-162-h1) shows Reiner Gamma's southwestern extension, and also the small swirl east of Lohrmann A.
- Research Lunar Orbiter 2 and 4 photographs: Danny Caes

IAU page: Reiner Gamma
Reiner Gamma is the most famous lunar swirl, and has an area of 10,000 km^2 and a strong magnetic anomaly (Hughes and others, 2006)
In the Topographic Lunar Maps prepared by the Army Map Service in 1963 Reiner Gamma was depicted as a shallow depression. It is presently thought to be purely an albedo feature with no vertical relief. - Jim Mosher
The bright oval, edged with dark is about 35 km in length. Splotchy bright material extends 200 km to the north and about 235 km to the south. - tychocrater Dec 26, 2009
The "official" diameter listed in the IAU Planetary Gazetteer is 70 km.
Reiner Gamma was selected as a Constellation Program Region of Interest (follow that link for more info).
Curious elongated rugby-ball shaped craterlet north-northwest of Reiner Gamma (LAT: 9.00 / LON: -59.61). See http://bit.ly/2xYJxme

See Reiner: "Gamma" is a Greek letter. In the notation of Blagg and Müller the name Reiner Gamma means a raised satellite feature of the crater Reiner.
According to Whitaker (pp. 65, 125 and 212), this formation (then thought to be a large crater) in the "Sea of Storms" was originally named for Galileo by Riccioli, who mistook it for a large crater. Mädler, who according to Whitaker recognized it as an albedo feature but did not give such things names, moved Galileo to a nearby, but much smaller, crater (the present Galilaei) and used the name Reiner Gamma to designate a ridge in the region, unrelated to the the albedo pattern. Despite what Whitaker says, Chuck Wood notes that Named Lunar Formations cites Mädler as its authority for the name Reiner Gamma, and that the Gamma on Mädler's map is in exactly the correct position. - Jim Mosher
Unlabeled in Elger's The Moon. Called Reiner R (for ruin) in Goodacre's The Moon and The Moon of Wilkins and Moore.
Called the Jew's Harp by Elger (see description at Galilaei).
Called Bullialdi by Van Langren (Langrenus).
Called Audus, mons by J.Hewelcke (Hevelius).

Recent Impact in Oceanus Procellarum (a tiny boulder-rich ray craterlet with flat central section, slightly east-northeast of Reiner Gamma).

L57: Conspicuous swirl & magnetic anomaly.