Scheduled time for Public Observing: 9pm – 11pm

Solar System Objects:

The Moon: will be 42° high in the SW at 9pm, and 36% illuminated (Waxing Crescent phase). The triple crater formation of Theophilus, Cyrillus, and Catharina is near the terminator tonight, each crater is about 60 miles across.

Image copyright (c) Virtual Moon Atlas /

Planets: Jupiter will be very low in the East, rising to 20 degrees altitude by 11pm. Although this is too low in the sky for observation with the observatory telescopes, it’s major satellites and a couple of cloud bands would be visible with any telescopes set up outside.

Image courtesy of Starry Night (R) Orion Special Edition, Version: 6.2.3 kcEW, Imaginova (R) Corp.

Deep-sky Objects:

Double stars: An interesting binary star in good position for observation tonight is Porrima, a.k.a. Gamma Virginis. It’s 38 light years away, the orbital period is 168 years, and the component stars are separated on average by about the distance from the Sun to Pluto. See the orbital diagram here. It has been followed through one complete orbit by astronomers, and even in amateur telescopes, the change in the star’s positions is evident within a few years. The 20″ refractor would be able to separate the stars without much difficulty.

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”.