Aristoteles and Eudoxus
Warm moist air from the south and cool dryer air from the north have been battling it out over the Chicago area for the last week. This morning the cold air was winning as the thermometer in my yard was reading 47°F. Fortunately the cold high pressure air mass was accompanied by better than average seeing and transparency.
The 20 day old waning gibbous moon was about 30° above the southern horizon at an hour and a half before sunrise. For sketching targets I chose Aristoteles and Eudoxus along the northern terminator. The view in my 10” f/5.7 Newtonian held up well at both 241X and 362X. I sketched at the eyepiece using both magnifications. Twin peaks on the floor of Aristotles were visible with the southeastern most peak surrounded by shadow. This 90 km Eratosthenian crater was displaying nicely terraced wall on the steep eastern side. Off to the terminator side (east) and overlapped by Aristoteles is the shadowed floor crater Mitchell (31 km.) an older Imbrian formation. Further north along the terminator margin is rim illuminated crater Galle which stretches 22 km in diameter and is about the same age as Aristoteles. The other large and younger crater to the south is Eudoxus (70 km.) which also has steep terraced walls. A small part of the Caucasus mountain range can be seen west and southwest of Eudoxus. Due west of Aristoteles the ancient eroded ghost-like crater Egede at 37 km in diameter can be seen in contrast to the younger craters named above.
Sketching:
For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’ pastel pencils and a blending stump. Brightness was slightly decreased after scanning.
Telescope: 10 inch f/ 5.7 Dobsonian and 6 and 4 mm eyepiece 241 and 362X
Date: 6-6-2007 9:05-10:00 UT
Temperature: 8° C (47° F)
Clear, calm
Seeing: Antoniadi II-III
Colongitude: 158.7 °
Lunation: 20.6 days
Illumination: 72.7 %
Frank McCabe