Cr121
Open Cluster in Canis Major
About
A loose group of young stars in Canis Major, about 3,590 light-years away and an estimated 12 million years old. Collinder counted 18–20 stars inside 60′ × 40′, while later Hipparcos work suggested a wider association of 105 stars. WR 6, a Wolf-Rayet star, coincides with the group, and Omicron1 Canis Majoris, a red supergiant, is closely tied to it.
Imaging tips
- At 400–670 mm on APS-C the cluster fills a third to half of the frame; on full frame use 620–1,030 mm.
- At magnitude 2.6 and 20.1 mag/arcsec² it is bright for a cluster; the stars are the subject, so broadband is the right choice.
- M41 lies a few degrees to the north, so it belongs in a wider field rather than the same frame.
- It stays low, peaking near 15° altitude from 50°N; best around December and January.
Facts
- Size
- 60′
- Magnitude
- 2.6
- Coordinates
- RA 6h 56.3m, Dec −24° 44′
- Framing, APS-C
- 400–670 mm
- Framing, full frame
- 620–1030 mm
- Best months
- Jan, Dec
- Peak altitude
- 15° from 50°N, 30° from 35°N