Dust and the Western Veil Nebula.

It's so big it is easy to miss. The entire Veil Nebula spans six times the diameter of the full moon , but is so dim you need binoculars to see it. The nebula was created about 15,000 years ago when a star in the constellation of the Swan ( Cygnus ) exploded. The spectacular explosion would have appeared brighter than even Venus for a week - but there is no known record of it. Pictured is the western edge of the still-expanding gas cloud. Notable gas filaments include the Witch's Broom Nebula on the upper left near the bright foreground star 52 Cygni , and Fleming's Triangular Wisp (formerly known as Pickering's Triangle ) running diagonally up the image middle. What is rarely imaged -- but seen in the featured long exposure across many color bands -- is the reflecting brown dust that runs vertically up the image left, dust likely created in the cool atmospheres of massive stars .