***This date has been changed, previously November 18.***
8pm – 10pm Deep Sky and outer planet observing
(Please note the time change from previous months)
The moon and any bright planets will not be visible tonight, but both Uranus and Neptune will be available for observation. Neptune will be better positioned early in the evening.
Graphics above courtesy of Starry Night (R) Orion Special Edition, Version: 6.2.3 kcEW, Imaginova (R) Corp.
Some of the moons shown above may be faintly visible in the 20″ refractor. Uranus and Neptune both appear small even in the 20″, but it’s interesting to keep in perspective what we’re seeing. Both planets are nearly the same size, the diameter of Uranus is 31,762 miles (almost exactly 4 times Earth’s diameter), and Neptune’s is 30,758 miles. The radius of Uranus’s orbit is 19 times that of Earths, and Neptune’s is 30 times.
The Summer constellations and center plane of the Milky Way galaxy are already well over in the West, making way for Fall constellations overhead and familiar Winter objects rising in the East. Different seasons offer different types of deep-sky objects for viewing. In the Fall we’re seeing a part of the galaxy where Open Clusters are numerous, although other objects are still visible.
The Perseus Double Cluster is a great example. Both clusters will fit into the field of view of a telescope using low power, covering an area a little larger than the full moon. In a dark sky, it is quite easily visible to the naked eye as a hazy patch between Perseus and Cassiopeia, and can be spectacular even in binoculars. They are 7,000 light-years from Earth.
Another famous example is the Pleiades, aka M45, Seven Sisters, and Subaru. Yes, the automaker used the name and stylized their logo. Easily visible to the naked eye at only 400 light years away, it’s best seen in binoculars or at very low power in a telescope.
The largest, brightest, and most easily visible galaxy in the Northern Sky is nearly straight overhead tonight. M31, the Andromeda Galaxy is 2 million light years away and about 2-1/2 times as large as the Milky Way. In a pristine dark sky, it’s full extent is at least 3 degrees (6 times the width of the full moon), best seen in large binoculars. From Middletown, the telescopic appearance is more like the (rather poor) image below.
For a better understanding, please see the image on Rob Gendler’s website (ASGH member).
The Blue Snowball (NGC 7662) is a good example and is still visible this time of year.
Double and Colored Stars