February 5, 2009
image by Jim Phillips
Linear rilles are flat-floored channels usually found paralleling edges of maria. The rilles form when the center of an impact basin and the maria within it subside, causing bending cracks along the edges. No basin is completely surrounded by these rilles - they all stop at some point. Jim's low Sun view of the Hypatia Rilles show that at least one linear rille previously extended further than it now does. The bottom, longer rille is Hypatia I and the shorter rille above it is Hypatia II (rilles are designated by Roman numbers). On most Clementine image suggests, the rille has been largely filled in by ray deposits (from Theophilus?).
Jan 31, 2009, 23:48-23:50 UT. TEC 200mm F/8 Flourite @ F/40.
Rükl plate 35
Yesterday's LPOD: The Great Wall of Procellarum
Tomorrow's LPOD: Up And Down, All Around