When the moon is several degrees below the summer ecliptic to the south, it can be
challenging to view and sketch from mid-northern latitudes.
I chose for sketching a highland region inside the triad of the Bays of Medii and
Aestuum and the Sea of Vapors. The center of this region contains the crater pair
Pallas and Murchison. Crater Pallas (50km.) which is a Nectarian period formation
is more than 3.8 billion years old. Pallas has a partially buried central peak at
1.3 km. above the lava flooded floor. Crater Pallas-A rests on the western rim and
deep bowl shaped crater Bode beyond the rim are clearly seen. Murchison (58 km.)
which is the oldest of the pair at about 4 billion years shows the greatest amount
of wear. Lava flooded floor, severe wall erosion, and strikes such as Chladni
(13.8km.) on the southeastern wall are among the features that demonstrate the age
of this crater. All that remains of the common wall of Pallas-Murchison are pieces
of ridge wall. Half of well known crater Triesnecker is visible to the east.
I was unable to use higher magnification because sky conditions were below average
until after moonset.
Sketching:
For this sketch I used: black Strathmore 400 Artagain paper, white and black Conte’
pastel pencils and a blending stump. Contrast and brightness were slightly
increased after scanning.
Telescope: 10 inch f/ 5.7 Dobsonian and 9 mm eyepiece 161X
Date: 7-23-2007, 1:15-1:48 UT
Temperature: 24° C (75° F)
Partly cloudy, calm
Seeing: Antoniadi III
Colongitude 10.1 °
Lunation 8.6 days
Illumination 58 %
Frank McCabe