8pm – 10pm          Deep Sky and outer planet observing

This is the last observing session for 2017, the dates for 2018 will be posted as soon as they’re available.

Please be prepared for cold temperatures, the observatory dome is not heated.

Moon and Planets

The moon will not be visible tonight, but Uranus and Neptune will be available, although Neptune will only be 30 degrees high at 8:00 and getting lower in the West. Uranus is well up in the sky at 57 degrees altitude. In the 20″ refractor, as well as moderate-sized amateur scopes, Uranus is easily visible as a planet and not just a pinpoint of light. Neptune appears smaller and fainter, but still non-stellar. They are both about 4 times the size of the earth, but Neptune is much farther away at about 2.7 billion miles as compared to 1.8 billion for Uranus.

Deep-sky objects

The central area of the Milky Way galaxy has set in the West this time of year, and our view is directed outward from the center towards the outer reaches of the galaxy. This changes the types of objects visible… there were many globular clusters visible in the summer, and now that’s changed to open clusters. Globulars are immense, condensed, and ancient clusters that are actually outside of the Milky Way in a spherical halo around it’s center, but gravitationally bound to the galaxy. Open clusters are smaller, much less condensed, and much younger clusters concentrated within the spiral arms of the Milky Way. They can also be very attractive in the eyepiece.

A famous example is M45, the Pleiades, visible to the naked eye in the East. Binoculars or a small telescope give the best view because of their wide field of view.

M45 courtesy Joe Roberts, an ASGH member. See also Joe’s website.

An amusing cluster is NGC 457 in Cassiopeia, probably best known as the ET cluster. Once you see it, you can’t un-see it.

Looking outward from the Milky Way, the largest and brightest “nearby” galaxy, M31 – the Andromeda Galaxy, is easily seen in a telescope nearly overhead. There has been some debate in the past, but it’s thought to be larger than our galaxy, 2 million light years away and containing about 1 trillion stars. From the light polluted skies of Middletown, just the central core is visible, but easily. The appearance is similar to the image below, made with a club member’s telescope and video camera, often set up outside the observatory on public nights.

See the link here for a description of ASGH member Rob Gendler’s amazing high-resolution image seen below.

By the end of the observing session another type of object, a diffuse nebula, The Great Orion nebula (M42) will be rising in the East, but we’ll save that for next month…