Hitchhiker's Guide to Rukl Chart 20

Lambert R (David North <d _at_ timocharis.com>)

Look for the huge ghost crater Lambert R.

Dorsum Zirkel (Matthew Buynoski)

I found the Dorsum Zirkel ridges interesting. Where it crossed the terminator, it broke into two parallel ridges, and left the impression that something (lava upwelling?) had heaved the two halves apart.

Little craters in the highlands were showing either a brilliantly lit outside of the front wall or a brighter inside of the back wall. In one case the entire circumference was lit up, like a ring. I suspect this variation must have something to do with the local tilt of the particular crater, or perhaps relative position/altitude with respect to the terminator. Comments, anyone? One would expect that craters near the terminator, all other things being equal, should have the outside of their sunward wall most illuminated, and as they rotate toward the sun, the back wall should then light up later.

Dorsum Zirkel Ray (...Akkana)

At 10:45 on August 1, 1998, with the terminator exactly through the crater marked "B" in Rukl, just north of Copernicus, a nice ray extended from the crater just north of "B".