H-NGC381
Open Cluster in Cassiopeia
About
An open cluster in Cassiopeia, roughly 3,100 to 3,500 light-years away depending on the source, with around 350 probable members counted down to magnitude 20. It is one of the Herschel 400 and also carries the name Collinder 10. Its members include no giant stars.
Imaging tips
- At 3460–5770 mm on APS-C the 7′ cluster fills a third to half of the frame, so it needs a long focal length rather than a wide lens.
- Faint for a cluster at 22.2 mag/arcsec². A visual observer counted roughly 30 dim, tightly packed stars spread over 7–8′.
- That observer doubted that the brighter stars strung out to its north are members, so they may share the frame without belonging to it.
- Within about 5° lie Gamma Cassiopeiae's nebula IC 59/63, NGC 225 and M103, so a wide lens could pair it with them.
- Best in September and October; it peaks near 78° altitude from 50°N.
Facts
- Size
- 7′
- Magnitude
- 9.3
- Coordinates
- RA 1h 8.3m, Dec +61° 35′
- Framing, APS-C
- 3460–5770 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Sep, Oct
- Peak altitude
- 78° from 50°N, 63° from 35°N