H-NGC2355
Open Cluster in Gemini
About
A compact open cluster in Gemini, listed in the Herschel 400 and also catalogued as Collinder 133. Roughly a billion years old, it is placed some 5,400 light-years from us and about 1,100 light-years off the Milky Way's mid-plane.
Imaging tips
- Only about 9′ across, so it suits a long focal length: at 2690–4490 mm on APS-C it fills a third to half of the frame.
- At magnitude 9.7 it is faint, with 23.1 mag/arcsec² surface brightness, so broadband data and generous integration suit it.
- John Herschel described its stars as very small, with magnitudes of 11 to 16, so most members are faint.
- Best around December and January, when it peaks near 54° from 50°N.
Facts
- Size
- 9′
- Magnitude
- 9.7
- Coordinates
- RA 7h 17.0m, Dec +13° 46′
- Framing, APS-C
- 2690–4490 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jan, Dec
- Peak altitude
- 54° from 50°N, 69° from 35°N