Sunset Ray on the Floor of Walther
Crater Walther (formerly known as Walter) lies on the southern lunar highland’s great peninsula facing almost directly toward the earth. This is an ancient land, high, heavily bombarded and Walther is a Necterian age, 145 kilometer member. This walled-plain crater has tall terraced walls that tower 4 kilometers above the crater floor. The off center central peak stands 1.6 kilometers above the surrounding floor. The ancient rim is heavily cratered and has several incisura along its circumference created by impacts. Before sunset and at just the right time light penetrates through a notch in the western rim and sprays light across the floor to the central peak and several floor crater rims beyond in an eastward direction. The remainder of the floor is completely dark creating the frozen searchlight view that I attempted to capture in this sketch. West of the notched wall is crater Deslandres W with its large rim blocks which separates it from the hellplain, Deslandres to the west. Walther also has a sunrise ray that can be seen beyond first quarter at just the right time.
The following webpage gives the times of lunar ray events for craters including Walther. http://www.lunar-occultations.com/rlo/rays/rays.htm
For this sketch I used: black Strathmore 400 Artagain paper, 8”x 8”, white and black Conte’pastel pencils and a blending stump. Brightness was slightly decreased after scanning.
Telescope: 10 inch f/ 5.7 Dobsonian and 6mm eyepiece 241x
Date: 11-2-2007 11:40-12:40 UT
Temperature: 0°C (32°F)
Seeing: Antoniadi III
Co longitude: 115.4°
Lunation: 22.3 days
Illumination: 43.6 %
Note to visitors: Frank dedicated this stunning sketch to Rich Handy last week in the Cloudy Nights sketching forum. Thank you Frank. I’m sure we all echo your wish that Rich have a speedy rebuild and return home.