Monday, October 3, 2011


This Saturday is International Observe the Moon Night - that means amateur astronomers around the globe will be setting up telescopes in public places.  If you're walking around in a busy place and you see a telescope on the street corner, don't be afraid.  Amateur astronomers are gentle and friendly creatures who only want to share their love of astronomy with you.  No need to approach with caution - just walk over and ask politely to see the Moon.

This is the perfect week to watch the Moon right after sunset.  When people see the Moon in a telescope their eyes light up. My favorite reaction comes from a 4th grader who did a double-take while looking through the eyepiece. “Man,” he commented, “the Moon sure got beat up!”

Peak in Tycho's Crater
Scarred with millions of craters, the Moon displays a violent past of meteoric impacts.  The most prominent crater, located on the southern half, is best seen at full Moon. The dynamic rays of crater Tycho radiate over 1,000 miles from its dark rim. Tycho is the newest, large impact with a diameter of 50 miles. The crater floor is almost 3 miles deep and features a central mountain peak over a mile high.

Most craters are best seen when they are located near the terminator – the line separating the illuminated from the dark surface. Just south of the center of the Moon you will find three dramatic craters named Ptolemaeus, Alphonsus, and Arzachel. With binoculars and telescopes, these crater walls can be seen with amazing contrast and clarity when the Moon is halfway lit up.