Observe on Lunar Day (after New Moon): 4 or 17
Lunar Day Seen: 17
Date/Time: 12/21/2021 21:28 Local Time
Location: 1425 Snowberry Lane, Broomfield, CO
Seeing: G
Transparency: 4
Instrument Used: 8" f/6 Newtonian Telescope
Magnification: 203x
Estimated Lunar Epoch: Late Imbrian
Actual Lunar Epoch: Upper Imbrian
Reasoning/Description: Nice view of crater. Most of rim wall piled high on east side. Not worn down. West side of this east rim bright facing the sun and helps to see the roughness fall off the other side. West rim wall is lower and looks like it's right at edge of Mare Frigoris's lava field. Atlas is on lava and next to a rougher highlands to the east. So Atas was made after the lava filling era. Maybe at end of the Post Imbriam era. No other creaters see on on rim walls. There are a couple of ghost craters near Atlas that are filled with lava. Only upper parts of their rim is showing. That's why I think whole area is a lava basin . The southeast part of rim wall stops abruptly. Was hard to capture that in the sketch. Not sure this east rim detail would have been this spectacular at sunrise here.
Sketch (click for larger image)
