Famously floor fractured

Lunar crater Petavius

The end of winter in the Midwest can sometimes produce cold, clear, wind free nights. On this particular night the waning gibbous Moon cleared the tall barren trees where I had set up my 10″ scope to observe and sketch. After examining the Moon awhile at low power I selected a target close to the terminator for sketching. Near the edge of the southeastern corner of the Sea of Fertility is the large ancient crater Petavius. Connected by a rampart to the west (just right of Petavius) is 57 km Wrottesley. To the east of Petavius buried deep in shadow is the Palitzsch Valley, asequence of overlapping craters that extends for nearly 112 km. The atmosphere was in such turmoil that much of the subtle detail was obscured at the time of this observation. The multiple mountain peaks on the floor of Petavius stood out as did the terraced walls and the 60 km long straight rille from the central peaks to the southwest rim. Even under conditions of poor seeing this is a rewarding crater to observe a couple of days past full Moon. If you missed it, try again 3 days past New Moon. From March to the end of spring the waxing crescent Moon is a great target in the Northern Hemisphere.

Frank McCabe

Sketch data:

For this sketch I used black Strathmore 400 Artagain paper 9″ x 12″, white and black Conte’ pastel pencils and a soft blending stump.

Telescope: 10 inch f/5.7 dobsonian and 6mm eyepiece

Date: 3-6-2007 2:45-3:30UT

Temperature: -6C (21 F) Clear Calm

Seeing: Antoniadi IV

Colongitude: 113.5 degrees

Lunation: 16.5 Days

Illumination: 95%