NGC 1857
Number of stars per data source
Reference 720 : 1 star
Reference 731 : 1 star
Reference 821 : 23 stars
Reference 1142 : 15 stars
References
- 720
- Guetter H.H.
- (1980) Publ. Astron. Soc. Pacific 92, 215
- UBV photoelectric photometry of 259 PZT stars
- 1980PASP...92..215G
- 731
- Guetter H.H., Hewitt A.V.
- (1984) Publ. Astron. Soc. Pacific 96, 441
- Photoelectric UBV photometry for 317 PZT and VZT stars
- 1984PASP...96..441G
- 821
- Purgathofer A.
- (1964) Ann. Univ. Sternw. Wien 26 no 2
- Dreifarben Photometrie in offenen Sternhaufen sowie in zwei Sternfelden in Cygnus
-
- 1142
- Babu G.S.D
- (1989) J. Astrophys. Astron. 10, 295
- Study of young open clusters as tracers of spiral features in our Galaxy. Paper 4: Czernik 20 (OCL 427)
- 1989JApA...10..295B