Lunar Terminator: Mare Spumans and Mare Undarum
By Frank McCabe (Mare Spumans and Mare Undarum)
- August 8th, 2012
- Posted in Black Paper . Conté Pencil . crater . maria . Moon . Pastels . White Conté on Black Paper
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On this evening, two days past full moon and with favorable libration on the eastern portion of the Moon, I chose two irregular maria targets for sketching. Mare Spumans was completely visible while Mare Undarum was only partly exposed beyond the terminator.
Although I have examined these little ancient “lakes” in the past this has been my first attempt to capture them on paper. Both are surrounded by bright, densely cratered upland and are close enough to Mare Crisium to be within its eject blanket and basin rings.
This is a very attractive region of the Moon for sketchers with craters Langrenus and Messier and Messier A nearby and Mare Crisium just to the north. I purposely kept these features out of my view to focus on lesser observed targets. In addition to the maria subjects, craters : Webb (22 km.), Apollonius (53 km.), and Firmicus (56 km.) provided eye catching targets across the view.
For this sketch I used: black Strathmore 400 Artagain paper 9″x 12″, white and black Conte’ pastel pencils and a blending stump. After scanning, Brightness was decreased just slightly using my scanner.
Telescope: 10 inch f/ 5.7 Dobsonian and 6 mm eyepiece 241x
Date: 08-04-2012, 04:00 – 05:50 UT
Temperature: 29°C (85° F)
Seeing: Antoniadi III
Colongitude 110.6 °
Lunation 16 days
Illumination: 94.9 %
Libration: in Lat. -5° 45’, in Long. +05° 38’