Ancient But Well Preserved

Crater Petavius

I have waited more than 2 years for conditions to be just right for re-sketching this magnificent crater. I got set up to observe under what looked to be hopeless circumstances. Although we have been under heavy cloud cover all week, the weather service forecasted clearing and as an added bonus my nearest “Clear Sky Chart” predicted the best possible seeing conditions until midnight. Both of these came true! Alas, heaven on earth.

Petavius crater (180 km.) is one of the best known and remarkable impact features on the lunar surface. It is a walled plain and floor fractured crater with impressive multiple central peaks (1.7 km), beautiful wall terraces, mare patches, volcanic ash regions, a raised floor and remarkable looking ramparts. In addition there is a special feature of this crater called Rimae Petavius. All three parts of this rille system could be seen clearly under the excellent seeing conditions that persisted during the entire observation. Connected to Petavius to the west is crater Wrottesley (57 km). South of Wrottesley the double rim of crater Petavius can be seen. There was so much detail visible in this area I could not hope to capture but a fraction of it.
Although Petavius is 3.8 billion years old it looks younger, stately and better preserved.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
pastel pencils and a hard blending stump.
Telescope: 10 inch f/ 5.7 Dobsonian with 6mm (241x) and 4 mm (362x) eyepieces
Date: 5-29-2009 1:20-3:15 UT
Temperature: 13°C (55°F)
Clear, calm
Seeing: Antoniadi mostly I, [ the collapsed lava tube down the center of Vallis Alps would have been easy under the seeing conditions of this night ]
Colongitude 329.5 degrees
Lunation 4.5 days
Illumination 28%
Moon was at Perigee just 3 days ago

Frank McCabe