Bob Moler's Ephemeris Blog

Ephemeris for Tuesday, October 23rd.  The sun will rise at 8:08.  It’ll be up for 10 hours and 35 minutes, setting at 6:44.   The moon, 2 days past first quarter, will set at 2:52 tomorrow morning.

Tonight the moon’s advancing sunrise line will reveal a young crater near the bottom of the moon.  That crater is Tycho.  In binoculars or a telescope it’s features appear sharper, and its floor deeper than the surrounding craters.  Its age is in the range of hundreds of thousands of years rather than billions.  Tycho has an extensive ray system that extends thousands of miles across the face of the moon.  That is best seen at full moon, and the rays are probably a huge number of craterlets.  They are normally shadow filled but at full moon are fully illuminated accentuating the brightness of the rays.  The crater was named for 16th Century Danish astronomer Tycho Brahe, the greatest observational astronomer before the invention of the telescope. [ His observations allowed Kepler to formulate his three laws of planetary motion.]

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

The crater Tycho and one of its rays at 9 p.m. on October 23 2012. Created using Virtual Moon Atlas.