For those that observe and sketch the Moon, trying to pick targets just before, just at and just after first quarter can be much fun because there are so many choices in good relief. On this occasion I chose two large walled plain craters near the terminator. Albategnius (129 km.) the younger of the two ancient craters and further from the terminator it was displaying its central peak (1.5km. tall) and large crater Klein (44 km.) on its rim. Crater Halley (36 km.) to the northeast is notably a kilometer deeper than Klein and although further from the terminator has a completely shadowed floor with that greater depth.
The other large crater Ptolemaeus (154km.) was on the terminator at the beginning of my sketch.
With the sun so low the rim shadows were long and were creating a special effect. In combination with the rim shadow of little crater Ammonius (8.5 km.) I could see old Nesse. Jim Adlhoch describes the floor shadow as looking like the head and neck of the Loch Ness monster- see Lunar Photo of the Day September 4, 2014.
http://lpod.wikispaces.com/September+4%2C+2014
Crater Ptolemaeus has a floor covered with many shallow bowl shaped craters, ghosts buried under lava. These ghost craters can be seen at low sun but the central peak is completely absent. To the north is crater Herschel (41 km.) with a shadowed floor.
Sketching:
For this sketch I used: Black Canson sketching paper, 10”x10”, white and black Conte’ pastel pencils and blending stumps.
Telescope: 13.1 inch f/ 6 Dobsonian and 9 mm eyepiece 222x
Date: 01-28-2015 00:05-02:00 UT
Temperature: -4°C (25°F)
Clear, calm
Seeing: Antoniadi II
Transparency: 4/5
Co longitude: 0.7°
Lunation: 7.20 days
Illumination: 56.1 %
Frank McCabe
