As the 2007 year began, winter’s cold grip had not yet taken hold. I was finishing
the process of cleaning and repairing a 13 inch Newtonian telescope when I decided
to colliminate and test the optics on the star Polaris and the moon. The moon was
one day past full and upper Imbrian period crater Humboldt in the
east-south-eastern sector of the libration zone was nicely placed for sketching.
Crater Humboldt at 207 km. in diameter is classified as a large floor fractured
crater. If this crater was 33% larger it would be a lunar basin. On the Lunar 100
list crater Humboldt is number 87.
At or near full moon many observers avoid looking moonward but old Luna can be a
rewarding telescope target at any and every phase.
Sketching:
I used a No. 2 HB pencil on copy paper for this drawing
Date: 1-4-2007 4:00 to 4:40 UT
Temperature: 0°C (33° F)
Windy, some mid-altitude cloudiness, seeing was average
Antoniadi : III
13.1 inch f / 5.9 Dobsonian 9mm ortho ocular 218X
Colongitude: 91.9°
Lunation: 14.6 days
Illumination: 99.6 %
Libration in longitude. +5.5°
Frank McCabe