Crater Cassini

  Day eight of a lunation is a favorite time to witness interesting light and shadow
play along the terminator from north to south. Crater Cassini is a very eye
catching crater and with a diameter of nearly 60km it is an attractive target for
telescopes of all sizes. At more than 3.5 billion years of age, Cassini is an old
battered nearly circular crater on the eastern edge of Mare Imbrium. The lava
basin around the crater appears mostly smooth and relatively dark. The ejecta
blanket immediately around this crater has an odd almost melted appearance. The
crater is shallow and the floor appears to be higher in elevation than the
surrounding mare; although this may be illusionary. Two large craters are visible
on Cassini’s floor. Crater A is the largest at 15 km.and the smaller B is about 9
km in diameter. Beyond the crater I sketched craters F, M and W all about 7 km in
size.
  Between Crater A on the floor of Cassini and the nearest inner wall is a series of
rilles and hills that resemble fish bones. At other times I have seen a nice dome
to the lower left (northeast) of Cassini but with the crater too far from the
sunrise terminator I could not pick it out.
  
  Sketching:
  For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
  pastel pencils and a  blending stump.
  Telescope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece 241X
  Date: 3-27-2007 12:15-1:20 UT
  Temperature: 20° C ( 69° F)
  Partly cloudy, calm
  Seeing:  Antoniadi  III
  Colongitude 8.5 °
  Lunation 8 days
  Illumination 63.5 %
  
  Frank McCabe