Theophilus

D= 99 km
Center: 11°S, 26°E

Count Area: 1306 km^2
Observed Density (@ 1km): 6100 ± 2200
Age: 3.0 ± 0.6 (+sec: 3.6)
Stoffler epoch: Eratosthenian
Fit Density (@ 1km): 3800 ± 1000
PF fit: good, smallest crater bin off, poor statistics, young, secondaries 

Age calculation notes:
? poor statistics (SM).
OK fit within error - one point off (steeper) - use as is; adding OSs worsens fit and produces older age (MRK).

USGS geology: 
All mapped as Copernican crater material. Smooth and hummocky units.

Wilhelms: 
Eratosthenian

Floor material: 
Best guess is original, but some edges near crater rim have sharp boundaries like an embayed feature. Also smooth floor. Peak large. Hard?

Geology Observations: 
Ejecta blanket visible, but not bright in WAC image. Larger central peak. Hummocky part to floor at 9:00 and 5:00 (ignored). Several secondary clusters/chains of moderate size (up to 1.3 km). Formed in mare. Landed on edge of similar sized crater.

SFD Observations: 
Dominated by class 2, but rest at not much lower density.  Class 3 abnormally high at ~ 700 m. Steeper distribution. No shallow "right ear". Slope(Diff)=-4.7 ± 1.0

Also examined by Baldwin (1985) and Neukum and Konig (1976).
Baldwin: density=3600 ± 320, age=1.826 ± 0.229 Ga, area=5114 km^2 (ejecta?)
Neukum: density=4800 (ejecta and interior)

Discussion notes: 
excess small craters - secondaries?

Last Edited by MRK 11/14/2012