| NGC 643 | |
|---|---|
 NGC 643 with DECam | |
| Observation data (J2000 epoch) | |
| Right ascension | 01h 35m 01.43s[1] |
| Declination | −75° 33′ 24.7″[1] |
| Distance | ~200,000 ly |
| Apparent magnitude (V) | 13[2] |
| Apparent dimensions (V) | 1.50 arcmin[3] |
| Physical characteristics | |
| Other designations | ESO 29-SC50 |
| Associations | |
| Constellation | Hydrus |
NGC 643 is an open cluster located on the far outskirts of the Small Magellanic Cloud in the southern constellation of Hydrus, approximately 200,000 light-years from Earth.[1][3][4] Due to their close proximity to NGC 643, the open cluster ESO 29-SC44 and the galaxies PGC 6117 and PGC 6256 are also designated NGC 643A, NGC 643B and NGC 643C, respectively.[4] NGC 643 is relatively old. Its brightest stars have an apparent magnitude of 19.[2]
- ^ a b c "NGC 643 NASA/IPAC Extragalactic Database Results". ned.ipac.caltech.edu. Retrieved November 1, 2018.
- ^ a b de Vaucouleurs, G. (1957). "NGC 643: A New Outlying Cluster of the Small Magellanic Cloud". Publications of the Astronomical Society of the Pacific. 69 (408): 252–255. Bibcode:1957PASP...69..252D. doi:10.1086/127060. JSTOR 40676443.
- ^ a b "Revised NGC Data for NGC 643". spider.seds.org. Retrieved November 1, 2018.
- ^ a b "New General Catalog Objects: NGC 600 - 649". cseligman.com. Retrieved November 1, 2018.