What it is
The Veil Nebula is what's left of a star that exploded as a supernova. The blast wave is still spreading outwards, and where it ploughs into the surrounding gas, the gas glows in these thin, braided filaments. The two bright arcs are the Eastern and Western Veil. The fainter wisps between them include Pickering's Triangle.
How far away
About 2,400 light-years, in the constellation Cygnus. The star exploded roughly 10,000 to 20,000 years ago. The whole loop spans about three degrees of sky, as wide as six full Moons side by side, but it is far too faint to see without a camera.
What it's made of
Mostly hydrogen and oxygen, heated by the shock. The different colours trace different gases in the filaments.