Wednesday, October 11, 2006

Cauchy and Fracastorius from 11th Oct 2006

I leapt out of bed at 3:30 this morning to check the seeing for observing the Moon. The seeing wasn't very good, It was misty with clouds that completely obscured the view sometimes.
I thought because of the mist that the seeing would be better, but it was affecting the focus, turning it very blurred at times.
I managed to get a couple of half decent images though and an hour later went back to bed. :-)

Cauchy is a small lunar impact crater on the eastern Mare Tranquillitatis. It is circular and symmetric, with a small interior floor at the mid-point of the sloping inner walls. Due to the high albedo of this bowl-shaped formation, it is particularly prominent at full moon. Just to the northeast of the rim of this crater is the wide rille named Rima Cauchy, a 210-kilometer-long cleft following a line to the northwest.

Southwest of Cauchy crater is a 120-km fault in the surface named the Rupes Cauchy. This wall parallels the Rima Cauchy to the northwest. South of Rupes Cauchy are two lunar domes designated Omega (ω) Cauchy and Tau (τ) Cauchy. They lie to the south and southwest of Cauchy crater respectively. Each lunar dome has a tiny craterlet at the crest.

AS8-13-2344.jpg via Kipp Teagues site

Orbiter Photo

Fracastorius is the lava-flooded remnant of an ancient lunar impact crater located at the southern edge of Mare Nectaris. To the northwest of this formation lies the Beaumont crater, while to the northeast is Rosse.

The northern wall of this crater is missing, with only mounds appearing in the lunar mare to mark the outline. The lava that formed Mare Nectaris also invaded this crater, so the structure now forms a bay-like extension. The remainder of the rim is heavily worn and covered in lesser impact craters, leaving little of the original rim intact. The maximum elevation of the rim is 2.4 km. The most prominent of these craters is 'Fractastorius D', which overlays a portion of the western rim.

The Fracastorius crater has no central peak, but a long, slender rille runs across the middle of the floor in a generally east-west direction.