| Nebula | |
|---|---|
 | |
| Observation data: J2000 epoch | |
| Right ascension | 20h 01m 53s |
| Declination | +33° 29′ 26″ |
| Distance | 6700 [1] pc |
| Apparent magnitude (V) | 11.4 |
| Apparent dimensions (V) | 0.63' x 0.63' [2] |
| Constellation | Cygnus |
| Designations | GC 4536, h 2062, Sh 2-99, Sh 2-100, PGC 3517682 |
NGC 6857 is an emission nebula and star-forming region [3] located in the constellation Cygnus. It is located in the Perseus arm of the galaxy. [4]
It was discovered by William Herschel on 6 September 1784. It was later observed by John Herschel, who believed it to be a star cluster. He described it as "A small bunch of very minute Milky Way stars, so small as almost to look nebulous; north preceding is another." Rudolph Minkowski would conclude in 1946 that NGC 6857 was a nebula.
The nebula is divided into two parts. The two parts are designated at Sh 2-99 and Sh 2-100. [5] It visually resembles a planetary nebula. [6]
Despite not being a galaxy, a PGC number was assigned to it by HyperLEDA. [7]
