The Milky Way, our home Galaxy seen edge-on, features many of the sky’s best sights, and summer is the ideal season to explore them. High overhead, a few degrees south of Epsilon Cygni, are two wonderful lace-like gaseous nebulae, forming together the Veil Nebula (NGC 6960 and NGC 6992-5).
Also known as the Cygnus Loop, the Veil Nebula is the twisted wreckage of a star that exploded as a supernova some 10,000 years ago. At an estimated distance of 1,500 light-years from us, at the time of the explosion the supernova would have been bright enough to cast strong shadows on Earth. Over time, the energy and material that was ejected into the interstellar medium has slowly expanded, and now the nebula covers an area of sky over seven times the diameter of the full Moon.
Though it was traditionally thought a difficult object to observe visually, the Veil Nebula is within the grasp of small telescopes. The easiest part of the nebula for amateurs to locate is NGC 6960. While not the brightest of the two large arcs, NGC 6960 runs directly through the wide 4th-magnitude double star 52 Cygni, making it the best place to start when studying the Veil. In a 6-inch or 8-inch telescope, NGC 6960 appears as a faint curved arc like a ghostly white rainbow, over 1° in length. With a narrow-band filter such as Orion’s Ultrablock or Lumicon’s UHC, the pale arc of nebulosity will stand out clearly, glowing against a black sky.
About 2.5° northeast from NGC 6960 is the largest and brightest portion of the Veil, NGC 6992-5. This side of the nebula is easily visible even with 7×50 binoculars and stretches for nearly a full 2° in large telescopes. Some of the filamentary structure inside the arc can be clearly distinguished, but most of it is only seen well on long-exposure photographs.
When hunting down the nebula a clear, dark sky is essential. Unless the Milky Way appears bright and richly detailed to the naked eye, you are likely to have trouble with the Veil. The telescope’s optics should be clean and free of dew or condensation, as even the slightest loss of contrast will spoil your view. Finally, use low powers – the Veil Nebula is very large and dim, so you will need to get as much light to your eye as possible.
Finder map – field width 15°, stars to magnitude +8.