Three Rings Around a Target

The Southwestern Limb of Moon with Montes Rook and Cordillera
Sketch and Details by Peter Mayhew

Object Name: Southwestern Limb of Moon with Montes Rook and Cordillera.

Object Type: Lunar mountains

Location:

Date: 3rd October 2009

Medium: Graphite pencil on white paper.

Instrument: Skywatcher Skyliner 150mm f8 Dobsonian, 10mm e.p. with x2 Barlow.

Seeing: Very turbulent with intermittent stillness.

The Montes Rook and Cordillera with labelled features
Sketch and Details by Peter Mayhew

The moon was 14 days old and this part of the south west limb was the only region under contrast. Craters were only visible when close to the terminator, or if rayed or darkened with basalt flows. The mountain peaks stood out perfectly in moments of stillness. The three concentric mountain rings around the (not-visible) Mare Orientale were clearly defined. I include a labelled version.