On this night I watched the sunset terminator move slowly toward ring-plain crater
Posidonius while I sketched the crater and nearby features on the floor of 750 km.
diameter Mare Serenitatis. Posidonius (99km.) is an old upper Imbrian era impact
reminant. Its age is betrayed by the way shadows penetrate the rim at numerous
points as the sun continued to set. The highest part of the rim is on the
terminator side of this crater. Sunlight was still reaching part of Posidonius A
and two other high points on ridges including one on the inner ring. Beyond this
crater to the west and south the great serpentine ridge could be seen in best
light. This ridge is made up of dorsa Smirnov and dorsa Lister just north of
crater Plinius (44 km.). Smaller and younger crater Dawes (19km.) could be seen
casting a shadow eastward which was growing in length throughout the sketch
interval.
Sketching:
2H graphite pencil, black felt tip marker on white copy paper, gum eraser
Date: 12-10-2006 8:05 to 8:40 UT
10 inch f / 5.7 Dobsonian 9mm ortho ocular 161X
Temperature: 3°C (37° F)
Clear, calm
Antoniadi: III-IV
Colongitude: 150.1°
Lunation: 19.4 days
Illumination: 71.2 %
Frank McCabe
Frank,
Once again a most excellent sketch that shows the many details around Posidonius, including an excellent portrayal of the Serpentine Ridge. Very nice indeed!
Wade,
This was a sketch I really enjoyed making. The rim of Posidonius looked to be on fire.
Frank