Open Clusters in Gemini
Messier 35 is the large group of bright stars on the left side of this image. It contains well over 100 bright stars, and it is an impressive sight through a telescope with a low-power eyepiece. The cluster is about 2700 light years away. Just 15 arc minutes to the southwest (in the lower right corner of this image) is a dense open cluster, NGC 2158, which appears smaller and dimmer than Messier 35 because it is about five times further away. Through a small telescope, the dim stars of NGC 2158 cannot be resolved, and the cluster appears as a faint circular glow on the outskirts of Messier 35. With my 18-inch Dobsonian and a high-power eyepiece, many of the individual stars of NGC 2158 can be resolved, and it makes a fascinating comparison with the much brighter Messier 35.
| Magnitude | 5.3 |
| Apparent Size | 25' |
| Distance (light yrs) | 2,800 |
| Right Ascension | 6:09.1 |
| Declination | +24 21 |
Image details: Exposure times of 22 minutes luminance and 10 minutes each of red, green and blue, taken with an SBIG STF-8300M imager and a 14" Meade telescope at f/4.8.
December 2023