Cosmic Pursuits

Basic astronomy and night sky information

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.

Book Excerpt: The Armchair Astronomer, Volume 1

by Brian Ventrudo Filed Under: Deep Sky

The “Heart Nebula” show the reddish glow of hydrogen atoms energized by bright stars that form inside this emission nebula. Lanes and patches of dark nebulae are also visible in the foreground of this star-forming region of the Milky Way.
The “Heart Nebula” show the reddish glow of hydrogen atoms energized by bright stars that form inside this emission nebula. Lanes and patches of dark nebulae are also visible in the foreground of this star-forming region of the Milky Way (Image by Terry Hancock).

(Today’s article is an excerpt of the book The Armchair Astronomer, Volume 1. It’s available from Cosmic Pursuits in multiple formats at this link).

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When 18th-century composer William Herschel grew restless with his life as a professional musician, he turned to the new science of astronomy for inspiration and challenge. Like most new stargazers, Herschel began by reading popular works of astronomy, learning the names of the stars and constellations, and inspecting the heavens with telescopes made with small glass lenses that collected the feeble light from distant stars [Read more…] about Book Excerpt: The Armchair Astronomer, Volume 1

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The Helix Nebula

by Brian Ventrudo Filed Under: Deep Sky

NGC 7293, the Helix Nebula, is a planetary nebula in the constellation Aquarius. Image credit: Warren Keller at Billionsand Billions.com. Additional credit: Piermario Gualdoni and Alessandro Cipolat Bares.
NGC 7293, the Helix Nebula, is a planetary nebula in the constellation Aquarius. Image credit: Warren Keller at Billionsand Billions.com. Additional credit: Piermario Gualdoni and Alessandro Cipolat Bares.

The showpiece of the constellation Aquarius is the grand and elusive Helix Nebula, NGC 7293. One of the closest and apparently largest of all planetary nebulae, the Helix is one of the few sights that’s easier to see in a small telescope than in a large one. In images, like the excellent collaboration above led by Warren Keller at BillionsandBillions.com, the nebula looks like an expansive eye in deep sky. Some refer to the Helix as the “Eye of God” [Read more…] about The Helix Nebula

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The Castaway Cluster

by Brian Ventrudo Filed Under: Deep Sky

The open star cluster NGC 6520, the "Castaway Cluster", and the dark foreground nebula Barnard 86. Credit: NOAO
The open star cluster NGC 6520, the “Castaway Cluster”, and the dark foreground nebula Barnard 86. Credit: NOAO

The Castaway Cluster, catalogued as NGC 6520, is located just above the spout in the “Teapot” of Sagittarius. This is a rich region of the Milky Way containing many gas clouds and star clusters, including the Lagoon and Trifid Nebulae. NGC 6520, a tiny jewel of a cluster, is often forgotten amongst these more famous sites [Read more…] about The Castaway Cluster

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IC 4665, the “HI” Star Cluster

by Brian Ventrudo Filed Under: Deep Sky

The open star cluster IC 4665 in the constellation Ophiuchus.
The open star cluster IC 4665 in the constellation Ophiuchus (credit: Wikipedia)

One of the best targets for a quick stargazing session this time of year is the pretty but underappreciated open star cluster IC 4665. It’s a snap to find, beautiful to behold, and like most sky sights on Cosmic Pursuits, it’s visible from the northern and southern hemispheres.

IC 4665 is spread out over a full degree, more than twice the diameter of the full Moon, so it looks fainter than its integrated magnitude of 4.7. In dark sky, IC4665 is just barely visible to the unaided eye roughly 1° NE of the star Celebrai in the constellation Ophiuchus. Celebrai, or β (beta) Ophiuchi, is one of the stars in the distinctive asterism called Taurus Poniatowski, the “little bull”. If you’re battling light pollution, you’ll need binoculars to spot the cluster [Read more…] about IC 4665, the “HI” Star Cluster

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View of the Veil Nebula

by Brian Ventrudo Filed Under: Deep Sky

Image of the eastern section of the Veil Nebula (NGC 6992 and NGC 6995). Credit: Jeff Johnson.
Image of the eastern section of the Veil Nebula (NGC 6992 and NGC 6995). Credit: Jeff Johnson.

The Veil Nebula is a sprawling supernova remnant in the constellation Cygnus and is one of the most intricate and beautiful objects visible with a small telescope. The nebula was formed by two stars that exploded 18,000 and 5,000 years ago, approximately. The stars were just 2,000 light years away, close enough to create a spectacular display when they detonated. Each must have shone as bright as a crescent Moon and cast shadows by night for weeks, but there are no records of these prehistoric events carved on a cave wall anywhere, at least none yet discovered [Read more…] about View of the Veil Nebula

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