Floor Fractured Crater: Furnerius

  Just two days past full moon, floor fractured crater Furnerius (125 km.) was well
placed relative to the sunset terminator to show off its interesting features.
This crater is one of the four large walled plain craters along the 60° E.
longitude line. Furnerius is the southern most of the four and placed not far from
the southeastern lunar limb. The other three which were visible at the eyepiece
from south to north but not sketched here are Petavius, Vendelinus and Langrenus.
Crater Furnerius is a pre-Nectarian crater and thus very ancient. It predates the
formation of the Nectaris basin. Basin debris and secondary impacts are scattered
across the floor and rim of this old battered crater. On the north side of the
crater floor a rille of 50 kilometers called Rima Furnerius can be seen. It
crosses the floor to the southeast and climbs the inner crater rim. Darker
smoother lava flooded areas can be seen on parts of the crater floor between the
rubble strewn regions created
 by the basin impact. Inner wall terraces and central peaks are completely absent
from this crater but large crater Furnerius B(22 km.) is clearly visible on the
floor. On the glacis of this crater to the north a bright young 12 km. crater
called Fernerius A can be viewed in line with Rima Furnerius. To the northwest a 75
km. Copernican era crater Stevinus, stands impressively with its sharp rim, central
mountain peak and low hills. South of Furnerius a smaller yet equally ancient
crater Fraunhofer (57 km.) was showing a dark flat half shadowed floor. On the
northwestern rim of this crater Fraunhofer V (24 km.) could be identified by a
small sliver of light striking its inner southeast rim.
  
  Sketching:
  
  For this sketch I used: black Strathmore 400 Artagain paper, 9”x12”, white and
black Conte’pastel pencils and a blending stump. Brightness was slightly decreased
after scanning.
  
  Telescope: 10 inch f/ 5.7 Dobsonian and 6mm eyepiece 241x
  Date: 10-28-2007 6:05-7:45 UT
  Temperature: 0.7°C (33°F)
  Clear, calm
  Seeing:  Antoniadi III- IV mostly poor
  Co longitude: 115.4°
  Lunation:  17 days
  Illumination:  93.7 %
  
  Frank McCabe