Upon the Sea of Clouds

Bullialdus Crater
Sketch and Details by Frank McCabe

Western Mare Nubium has been the home of complex, Eratosthenian period crater Bullialdus (61 km.) for the past three and a half billion years. The beautifully terraced inner walls to the east and kilometer high central peaks were clearly seen in the morning light. The outer downward sloping walls were showing alternating radial ridges and valleys down to the lava flooded floor of Nubium. The crater rim stands 2.4 kilometers above the crater floor and the floor is 1.2 kilometers below the surrounding Mare Nubium lava.
The ancient flow of lava across the Sea of Clouds breached the walls and flooded the floors of craters Kies (44 km.) to the southeast and Lubiniezky (44 km.) to the northwest of Bullialdus. Immediately to the south of Bullialdus are Bullialdus A and B, both twenty something kilometers in diameter with the closer A being the larger of the two. The famous 11 kilometer dome Kies л was clearly seen just to the west of crater Kies and to the northwest, crater König (23 km.) looked impressive with its dark shaded floor.

Sketching:

For this sketch I used: black Strathmore 400 Artagain paper, 9”x 12”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased (-3) and contrast increased (+2) after scanning using Microsoft Office Picture Manager.

Telescope: 10 inch f/ 5.7 Dobsonian and 6mm eyepiece 241x
Date: 5-15-2008 2:10 – 3:45 UT
Temperature: 8° C (46° F)
passing clouds, calm
Seeing: Antoniadi III
Co-longitude: 28.8°
Lunation: 9.6 days
Illumination: 78.5 %
Phase: 55.3°
Observing Location: +41°37′ +87° 47′

Frank McCabe