Deep Sky Observing

Articles about how to understand, find, and see celestial objects including stars, galaxies, nebulae, and star clusters with binoculars, telescopes, and the naked eye.

The Allure of Carbon Stars

January 27, 2017 by Brian Ventrudo Filed Under: Deep Sky

The carbon star R Leporis. Credit: Damian Peach

For visual observers with small optics, the colors of the deep sky range from subtle to nonexistent. Galaxies and nebulae cast too little light to stimulate the color-sensing cone cells in our retinas, so they appear pale gray-white or, in the case of a bright planetary nebulae, gray-green. Bright stars are a little more colorful. Betelgeuse appears clearly orange, even to the unaided eye, Rigel shines blue-white, and the showpiece double star Albireo in the constellation Cygnus shows off a blue-green primary and red-orange secondary in even the smallest telescope. Otherwise, star colors are quite subtle, especially to new stargazers. But there is one exception– carbon stars. These deep ruby-red stars, which dredge up nuclear soot from their innards, give off a striking glow that’s easy to see in a small telescope. See your first carbon star and you’ll want to see many more [Read more…] about The Allure of Carbon Stars

Share This:

The Attendants of Mirfak

January 19, 2017 by Brian Ventrudo Filed Under: Deep Sky

The star Mirfak and its 'Attendants', the cluster known as Melotte 20, are at the bottom of this image, just right of center. Closer to the center of the image, just rightward, lies the famous Double Cluster. — The star Mirfak and its ‘Attendants’, the cluster known as Melotte 20, are at the bottom of this image, just right of center. Closer to the center of the image, just rightward, lies the famous Double Cluster.

Nearly overhead in the after-dinner hours of a northern winter night, the rich constellation Perseus offers even a modestly-equipped amateur astronomer many hours of pleasant stargazing. Named after the great hero of Greek mythology, Perseus finds itself in the starry plane of the Milky Way Galaxy where thousands of brilliant blue-white stars have coalesced in the the last few tens of millions of years. Near the star Mirfak, or α (alpha) Persei, the brightest star in Perseus, lies a particularly dazzling collection of associated blue-white stars that make up a loose cluster often called the “Attendants of Mirfak”. This little group is a beautiful sight in binoculars [Read more…] about The Attendants of Mirfak

Share This:

Three Clusters and a Cheshire Cat

January 13, 2017 by Brian Ventrudo Filed Under: Deep Sky

The stars along the northern Milky Way rising in the eastern sky. To the right lies the Hyades above which is the smaller Pleiades star cluster. To the right lies the constellation Auriga, the Charioteer. — The stars along the northern Milky Way rising in the eastern sky. To the right lies the Hyades above which is the smaller Pleiades star cluster. To the left of center in this image lies the constellation Auriga, the Charioteer.

Visible nearly overhead in the northern hemisphere, the bright constellation Auriga makes for pleasant viewing this time of year. The constellation, which looks like a big hexagon about 15° across, sits in a fine star field along the northern Milky Way directly opposite the much richer sky near the galactic center in Sagittarius. Auriga also holds the dazzling star Capella, the most northerly first-magnitude star in the skies. The constellation is also visible above the northern horizon from most populated parts of the southern hemisphere. Whether you have a pair of binoculars or a small telescope, make an appointment to examine the three finest open star clusters of Auriga– M36, M37, and M38– along with a smiling asterism embedded in the stream of the Milky Way [Read more…] about Three Clusters and a Cheshire Cat

Share This:

Two Fine Galaxies in the Sculptor Group

October 14, 2016 by Brian Ventrudo Filed Under: Deep Sky

Image of NGC 55 acquired by Brett Soames of NSW, Australia and processed by Warren Keller at www.billionsandbillions.com. — Image of galaxy NGC 55 acquired by Brett Soames of NSW, Australia and processed by Warren Keller at www.billionsandbillions.com.

One of the closest congregations of galaxies to our own, the Sculptor Group consists of a series of relatively bright and shapely galaxies clustered in the barren sky near the south galactic pole. The group is anchored by the majestic NGC 253, the Silver Coin Galaxy, one of the most beautiful galaxies for a small telescope. But a little farther south lie two more gems, NGC 55, also called the ‘String of Pearls’, and NGC 300, one of a handful of galaxies known as the ‘Southern Pinwheel’. For northern observers, this pair is low in the thick air over the southern horizon in the late months of the year. Southern-hemisphere observers, however, see these galaxies nearly overhead where it’s much easier to see their distinctive shape and features in a small telescope [Read more…] about Two Fine Galaxies in the Sculptor Group

Share This:

IC342: An Obscured Spiral Galaxy, Hiding in Plain Sight

October 7, 2016 by Brian Ventrudo Filed Under: Deep Sky

The nearly face-on spiral galaxy IC342 (Caldwell 5) in the constellation Cepheus. Image credit: Terry Hancock. — The nearly face-on spiral galaxy IC342 (Caldwell 5) in the constellation Camelopardalis. Image credit: Terry Hancock.

The galaxy IC342 ranks as one of the under-appreciated gems of the northern night sky. As you can see in the image above, this elegant nearby spiral galaxy in the far-northern constellation Camelopardalis (the Giraffe) is a photogenic target for experienced imagers. But it’s rather challenging to see visually in all but the darkest skies. It is, however, worth the effort to see this swirling assembly because it lies in an unusually beautiful field of foreground stars [Read more…] about IC342: An Obscured Spiral Galaxy, Hiding in Plain Sight

Share This: