Bob Moler's Ephemeris Blog

Ephemeris for Thursday, April 18th.  The sun rises at 6:52.  It’ll be up for 13 hours and 38 minutes, setting at 8:31.   The moon, at first quarter today, will set at 3:21 tomorrow morning.

Lets take a look at the moon tonight.  It’ll be about 6 hours after first quarter and we’ll see features at the terminator, the sunrise line that cuts the moon in half.  In small telescopes, at the north or top end of the moon, the wide flat  crater Plato is just entering sunlight.  Long shadows from its crater walls will retreat across its flat floor over the evening. If you look closely you’ll notice that the floor of Plato is slightly convex to conform with the curvature of the moon itself.  Nearby is the straight gash in the Alps Mountains, called the Alpine Valley.  Supposedly the crater Plato formed shortly after Mare Imbrium formed throwing up the Alps and the Apennine mountains to the south.  The Straight wall, can be seen on the south end of the moon.

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

Addendum

First quarter moon April 18, 2013 Created using Virtual Moon Atlas