M67 — King Cobra Cluster
Open Cluster in Cancer
About
NGC 2682, one of the oldest known open clusters, in Cancer about 2,600–2,900 light-years away. It holds well over 100 Sun-like stars and many red giants, and five of its stars have exoplanets found by radial velocity. It is sometimes called the King Cobra Cluster.
Imaging tips
- About 25′ across, so 970–1,620 mm on APS-C spans a third to half of the frame, or 1,490–2,480 mm on full frame.
- One remote LRGB run gathered about 5.8 hours in 87 frames of roughly 3–4.5 minutes; a 16-inch with an f/6.3 reducer used 15 × 2 minutes per colour.
- Star colour is the draw: the 16-inch team boosted star colour in processing and shrank the stars afterwards.
- At 22.5 mag/arcsec² it is a loose cluster with no nebulosity, so broadband is the right choice.
- Best around January and February; it stays below 52° altitude from 50°N.
Facts
- Size
- 25′
- Magnitude
- 6.9
- Coordinates
- RA 8h 51.5m, Dec +11° 49′
- Framing, APS-C
- 970–1620 mm
- Framing, full frame
- 1490–2480 mm
- Best months
- Jan, Feb
- Peak altitude
- 52° from 50°N, 67° from 35°N