| NGC 2158 | |
| Class: | II3r |
| Epoch: | J2000 |
| Ra: | [1] |
| Dist Ly: | 11,000+ ly[2] |
| Appmag V: | 8.6 |
| Size V: | 5 arcmin |
| Radius Ly: | 8 ly |
| Age: | ~2 billion yrs |
| Constellation: | Gemini |
NGC 2158 is an open cluster in the constellation of Gemini. It is, in angle, immediately southwest of open cluster Messier 35, and is believed to be about 2 billion years old. The two clusters are unrelated, as the subject is around 9,000 light years further away.
Once thought to be a globular cluster, it is now known to be an intermediate-age, metal-poor open cluster that is a member of the old thin disk population.