Lunar Terminator Near to the Western Limb
On Sunday evening I was getting a wonderful view of the lunar terminator near the western limb just a half day before full Moon. The favorable longitudinal libration of -04° 40’ was creating an opportunity to see craters along the terminator that are often poorly placed for viewing.
With storms on the way from the southwest this was a good evening to attempt a sketch. The calm before the arrival of storms often leaves the seeing fair to good as was the case on this night. Craters such as Vasco da Gama (99 km.), Bohr (73 km.), Dalton (63 km.), Balboa (71 km.) and part of Einstein (175 km.) were all seen. Craters Cardanus (51 km.) and Krafft (53 km.) and the crater chain (catena) between them were in bright sunlight. The views all along the terminator were magnificent.
For this sketch I used: black Strathmore 400 Artagain paper (9” x 12”), white and black Conte’
pastel pencils. In addition a small artist’s brush and powdered Conte’ white crayon was used for blending. Contrast was slightly increased (+2) using a scanner to better match the original.
Telescope: 13.1 inch f/ 5.9 Dobsonian and 6 mm eyepiece 327 X
Date: 02-25-2013, 04:00-06:30 UT
Temperature: 0.0° C (32° F)
Partly cloudy, calm
Seeing: Antoniadi III
Colongitude 86.9 °
Lunation 14.87 days
Illumination 99.5 %