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Two Cygnus Nebulae
Two Cygnus Nebulae

With Cygnus high in the eastern sky this month after the start of astronomical dark, two interesting nebulae can be part of your list of observing targets for dark skies. The more famous is the Cygnus Loop, more commonly known as the Veil Nebula. Its location makes for an easy find, with the brighter of its two main sections crossing the naked-eye star 52 Cygni close by the western wing of the constellation figure.

Veil Nebula - Witch's Broom section with 52 Cygni

If you star hop, start with (A) Alpha Cygni, Deneb moving six degrees southwest to (G) Gamma, the center star of the Northern Cross asterism. Proceed south-southeast along the eastern wing eight degrees to (Ep) Epsilon, leaving a quick jump three degrees southeast to 52 Cygni, shining at magnitude 4.2, and your target.

With the star centered in your finder, use a low power eyepiece fitted with an Oxygen III filter. At first view, you'll immediately note the odd color of the star, but that's just the filter. Next a thin tubular shape passing across the star will become apparent, appearing transparent and three dimensional. This is the bright section of the Veil Nebula known as the Witch's Broom. It will fill your eyepiece with the star centered. What is it? This is a section of supernova remnant expanding through space as a shockwave ionizing.

Approximately the size of the full moon, another bright section of the Veil Nebula is called The Waterfall — much wider, appearing as a shredded stream of matter.

The second object on this tour is called the Crescent Nebula. Instead of a supernova explosion ionizing interstellar atoms, this glowing oval is the result of a particular rare type of star, known as a Wolf-Rayet, known for high temperatures, heavy elements and strong stellar winds, thousands of times the luminosity of our Sun.

Cataloged as NGC 6888, this object lies along the major axis of the Swan, or Northern Cross. View it from dark skies by using your finder to hop from (G) Gamma Cygni approximately one third the distance to (Et) Eta Cygni. You'll benefit from a narrowband filter to darken the background and allow only the nebula's light wavelengths through; otherwise, this target will be very difficult. At a distance of 5,000 light years, the Crescent measures 18' x 12' in size, with an oval shape varying in brightness and thickness, with a section that extends in toward the ionizing Wolf-Rayet star. Once you've found this target, it likely will become a favorite along with the larger, and easier, Veil.

Mark Wagner is a life-long astronomy enthusiast and deep sky observer. He has spent the past twenty years popularizing amateur astronomy in the San Francisco Bay Area through his writing and community building. A past president of the San Jose Astronomical Association, he founded what is now the annual Golden State Star Party in California.

Date Taken: 06/30/2022
Author: Mark Wagner
Category: Weekly

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