面纱星云是在天鹅座的一团由高温与电离的气体和尘埃组成的云，它构成了天鹅圈（电波源W 78，或Sharpless 103）的可见部分，一个巨大但相对暗淡的超新星残骸。来源的超新星爆炸大约发生在5,000至8,000年前，从爆炸迄今残余的物质大约涵盖了直径约3度的范围（大约6倍的月球视直径，或36个满月的范围）。这个星云的确实距离仍不清楚，但是 FUSE的测量证实距离大约是1,470光年。

哈伯太空望远镜拍摄了数个这个星云的影像，分析来自星云的发射，显示存在着氧、硫、和氢；在X射线的天空它也是最大和最亮的一个特征。

The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It constitutes the visible portions of the Cygnus Loop (radio source W78, or Sharpless 103), a large but relatively faint supernova remnant. The source supernova exploded some 5,000 to 8,000 years ago, and the remnants have since expanded to cover an area roughly 3 degrees in diameter (about 6 times the diameter, or 36 times the area, of the full moon). The distance to the nebula is not precisely known, but Far Ultraviolet Spectroscopic Explorer (FUSE) data supports a distance of about 1,470 light-years.