Galactic Nebula Sh 2-227 + Open Cluster NGC 1857
History
On 18 October 1786 William Herschel discovered the open cluster NGC 1857 which he listed as VII 33 and noted: «A cluster of pretty compressed pretty small stars, considerably rich, contains one large star, the rest are all of a size.» [464] On 3 Feb 1832 (sweep 399), John Herschel listed the cluster as h 350 and recorded: «A star 7 mag, very ruddy, almost orange-coloured, in a pretty rech cluster of very small stars.» [466]
While searching the photo plates of the «Palomar Observatory Sky Survey» made with the 48 inch Schmidt telescope, the American astronomer Stewart Sharpless came across the emission nebula Sh 2-227 and published it in 1959 together with a total of 313 H-II Regions in a catalog. [310] In 1965 Beverly T. Lynds published her «Catalogue of Bright Nebulae» that she found on photo plates of the «National Geographic Palomar Observatory Sky Atlas». She listed there Sh 2-227 as LBN 168.71+00.89 (LBN 781). [270]
Physical Properties
| Name | Type | RA (J2000.0) |
Dec (J2000.0) |
PM [mas/y] |
Parall. [mas] |
Rvel [km/s] |
z | Size ['] |
Magnitudes | Identifiers |
|---|---|---|---|---|---|---|---|---|---|---|
| NGC 1857 | OpC | 05h 20m 07s | +39° 20' 10" | 0.553 | 0.32 | 1.3 | 0.000004 | 7.4 × 7.4 | B 8.08; V 7 | C 0516+393; NGC 1857; OCl 428.0; [FSR2007] 0755; [KPS2012] MWSC 0505 |
| Sh 2-227 | HII | 05h 19m 48s | +38° 57' 00" | LBN 168.71+00.89; LBN 781; SH 2-227 |
Finder Chart
The open cluster NGC 1857 and nebulae Sh 2-227 are located in the pentagon of the constellation Auriga, roughly 1° south of 4.7 mag double star λ Aurigae. The best observation time is August to April. At about 12 December they are in opposition to the Sun and crosses the meridian at local midnight.
