Billy Crater and Mons Hansteen

Observation Notes:

After spending time on Shickard, I moved Northward to Billy Crater. It showed a nice intact rim with a dark flooded floor. There were two white splashes on the south-southwest and south-southeast ends of the crater floor. Immediately north of the crater was a bright white spray that radiated southward. A broad road of lighter material flowed away from the west side of the crater and curved northwest.


Billy Crater is a 46 km wide crater with a 1300 m high rim. Its floor is one of the darkest spots on the moon. It was formed more than 3.2 billion years ago–prior to the lava flows that filled Oceanus Procellarum. The “bright spray” I saw north of Billy is a 30 km wide massif called Mons Hansteen

Subject Billy Crater and Mons Hansteen
Classification Lunar Crater and Mountain
Position West edge
Phase/Age 12 days old
Size* Billy Crater: (dia. 46 km);
Mons Hansteen (width 30 km)
Date/Time January 22, 2005 – 10:05 PM (January 23, 2005 – 05:05 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 10 mm + 2X Barlow (240X)
Conditions Clear, cool (34°F)
Seeing 4-5/10
Sources The Moon Observer’s Guide By Peter Grego

* Based on published data.