Scheduled time for Public Observing: 8pm – 10pm

**With a predicted temperature of 25°F during the observing session, please be aware that although the observatory building is heated, the dome itself is not, because it would interfere with viewing through the telescope. Experience shows that wearing multiple layers really does work.**

Solar System Objects:

The Moon: will be 52° high in the SE at 8pm, and 83% illuminated (Waxing Gibbous phase). The flat, circular feature named Mare Imbrium is actually a huge impact crater, among the largest in the Solar System.

Image (c) Virtual Moon Atlas /

It’s approximately 700 miles in diameter. The proto-planetary object that created it slammed into the Moon 3.8 billion years ago, and is estimated to have been 150 miles in diameter. Lava flooded the basin after the impact and created the smooth, dark surface. The mountain ranges outlining Mare Imbrium are up to 4 miles high.

Planets: Uranus and Neptune will both be observable with a telescope tonight, although Neptune will be getting quite low in the West. Uranus will appear only about 7 degrees above the Moon.

Double Stars:

And about 7 degrees above Uranus is the double star Gamma Arietis, or Mesartim. It’s about 164 light-years away, the two components appear blue-white in color and evenly matched in brightness. It is a true binary star, with an orbital period greater than 5,000 years. The stars are about 2-1/2 times larger than the Sun, and 50 times brighter!

Star Charts and other Information:

A very useful monthly star chart can be downloaded here from, giving information on objects visible with the unaided eye, binoculars, or telescope.

For current astronomical events see Sky and Telescope Magazine’s “This Week’s Sky at a Glance”.