As the moon approaches full phase the sun will eventually rise on the well known triple crater group: Phocylides, Nasmyth and Wargentin. The 117 kilometer diameter walled plain crater known as Phocylides is situated south southwest of the more famous impact remnant known as Schickard (233 km.). At the time of my observation and sketch the terminator was crossing over Phocylides and presenting an impressive view for an attempt at a quick sketch. This ancient formation (Nectarian) was just beginning to catch sunlight on its inner western wall. The crater looked much larger than usual because hidden in that darkness is also crater Nasmyth (80 km.), its far western wall also illuminated but not its floor, central peak or common wall with Phocylides. When at higher sun it is easy to tell that Nasmyth is the older crater since the wall of Phocylides intrudes into Nasmyth at their common divide. There is a third member to this group and it is an interesting crater with lava filling it to the brim. It is crater Wargentin (87 km.) but unfortunately it remained hidden during the entire observation.
For this sketch I used: white sketching paper 12â€x 10â€, HB, 4B, 6B graphite pencils, a blending stump. After scanning, Brightness was decreased (-2) and contrast increased (+2) using Microsoft Office Picture Manager.
Telescope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece 241x
Date: 8-3-2009, 3:00 - 4:00 UT
Temperature: 22Â° C (72Â° F)
clear, breezy, 70% humidity
Seeing: Antoniadi III
Lunation 12 days
Illumination 93 %