Credit: Aldo Zanetti
Astronomical and Imaging Data
| RA: | 17h 27m 08.50s |
| DEC: | -07° 05′ 35.0″ |
| MAG: | 13.1 |
| Diameter: | 4.95′ |
| Const: | Oph |
| OTA | RD 12″ |
| Focal Length | 2432mm |
| Camera | PlayerOne Poseidon M |
| Site | Central Italy |
| Sky Quality | Bortle 4 |
Useful Informations
IC 1257 is a faint, compact globular cluster located in the constellation Ophiuchus. Its distance and position in the outer halo of the Milky Way make it a valuable subject for studying the properties of our galaxy’s outskirts. It was initially a challenge to identify as a globular cluster due to its faintness and compact size, but a color-magnitude diagram confirmed its nature.
Physical and Scientific Properties
- Apparent Magnitude: IC 1257 has an apparent visual magnitude of approximately 13.1, making it an extremely faint object that can only be observed with a powerful telescope.
- Diameter: The cluster has an apparent angular diameter of roughly 4.9 arcminutes. At its distance, this corresponds to a physical diameter of around 120 light-years.
- Distance and Location: IC 1257 is a very distant cluster, located approximately 81,500 light-years from Earth and about 58,400 light-years from the Galactic Center. This remote position is significant because it allows astronomers to study a star system that is relatively free from the tidal forces and obscuring dust found closer to the galactic disk and bulge.
- Metallicity: Scientific analysis of its stellar population reveals that IC 1257 is a metal-poor cluster. While specific metallicity values may vary between studies, it fits the profile of other globular clusters in the outer halo, which are generally composed of older, more pristine stellar populations with lower abundances of elements heavier than hydrogen and helium.