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                                    Left.  Ridge Section 81; Right: Cropped 1200 dpi USGS color chart of Section 81                                            

Larger version of region
This area is out of frame not on the USGS Far Side Charts
Lunascan Quad Composite of Sections 80, 81 & 88, 89 & 88
LRO Wide Angle Camera 8 in pdf (Stebbins)
LRO  Wide Angle Camera 19 in pdf (Birkhoff & Rowland)

58.7_N_146.1_W

Birkhoff is a giant lunar walled plain that is located on the lunar Far Side. In the northern hermisphere this formation is an ancient impact site that has been heavily eroded, and the surface reshaped by multiple craters in the interior and along the rim. The outer wall is bordered by the craters Carnot to the south (out of frame), Rowland along the west rim, and Stebbins to the northeast. What remains of the perimeter is now a rugged sloping rise along the inner wall, and the rim has been worn down until it is level with the irregular external terrain. The rim is pock-marked by small craters of various dimensions. Within the crater are several craters that are notable in their own right. Along the northwest inner rim is the eroded Birkhoff X, while due south in the southwest floor is Birkhoff Q. The latter is joined by a low ridge to the double crater formation of Birkhoff K and L in the eastern half of the crater. In the northern interior are the smaller but relatively young Birkhoff Y and Z. The remainder of the floor is flat in places, with rough sections and many tiny craterlets.. (Credit: Some of the information used in the section feature descriptions was obtained from wikipedia.org.  Section 81 and this directory was created by Fran Ridge and Ned Haskin of The Lunascan Project).