It remined me a lot of Copernicus with its teraced walls, stunning central peaks, and detailed floor. But Petavius is also very different to Copernicus. The ray system is highly erroded from a more concentrated subsequent impacts, and the remant ray system to its south is very, very jagged. Might just be an illusion though due to the position of Petavius close to the Moon's limb, and Coperincus more central. But the effect is of a very nasty Moonscape.
Petavius also has an impressive rile running through its floor. Probably from fracturing of the surface - Petavius is a very ancient crater.
Being situated in a highly cratered section of the Moon, the surrounds of Petavius is complex, textured and tortured. There are very fresh impacts, and highly erroded ones. One such near obliterated crater sits just to the south (right) of the crater Snellius. There are three craters that trace a short arc around Snellius. The top one is the most erroded, with only a soft shadow of the depression remaining due to the innumerable smaller impacts. The crater just below this "shadow" is also highly erroded, but to a lesser extent, but also on its way to oblivion. And the third (S. A) I've just included its sharp illuminated eastern wall. The trio made for an impressive example of lunar errosion.
Snellius also has a rile running through its floor. Finer than that of Petavius.
I learnt a lot from this sketch. The time taken to observe each little section allows for a much more concentrated examination of the lunar surface. The erroded trio was one such little treasure of me. Another was a more technical one where I found a way to depict the variations of illumination by fixing the finished sketch, and then the application of the white ink has less bleed into it from the pastel and charcoal, making it even brighter.
Object: crater Petavius and surrounds
Scope: C8, 8" SCT
Gear: 9mm TMB Planetary Type II, 222X
Date: 4th August, 2012
Location: Sydney, Australia
Media: Soft pastel, charcoal, white ink and china graph on black paper