C33 · Eastern Veil Nebula
| Chinese name | 东面纱星云 |
|---|---|
| Type | Supernova remnant |
| Constellation | Cyg |
| RA | 20h56m |
| Dec | +31° |
| Apparent magnitude | 7ᵐ |
| Hemisphere | Northern |
| Best season | Summer |
| Difficulty | Moderate |
| Focal length | 中焦 400–800mm |
About
The Eastern Veil Nebula (C33, NGC 6992) is the eastern half of the Cygnus Loop supernova remnant, lying about 2,400 light-years away in Cygnus. The whole Cygnus Loop stems from the supernova of a massive star some 10,000 to 20,000 years ago, and its expanding shock still sweeps through the interstellar medium at hundreds of kilometers per second, the heated gas glowing in delicate, lace-like filaments. It shows twin tones of red hydrogen and teal oxygen, the former from cooler zones and the latter from the hot shock front. The full remnant spans six full-moon widths, and the Eastern Veil is its brightest, finest section. Narrowband imaging reveals stunning layers of filaments, making it a star remnant of late summer into autumn.