H-NGC436
Open Cluster in Cassiopeia
About
A small open cluster in Cassiopeia, about 9,800 light-years away and estimated at 85 million years old, listed in the Herschel 400 and also as Collinder 11. William Herschel found it in 1787. It lies in the same region as the larger Owl Cluster, NGC 457.
Imaging tips
- Sources give about 5′, which is too small to frame: use a long focal length and a fine pixel scale.
- Broadband imaging suits a cluster; one imager took 30 minutes of luminance plus 20 minutes each of red, green and blue.
- NGC 457 is a brighter, larger neighbour at about 7,900 light-years; one imager framed both with a 10-inch f/3.6 astrograph, NGC 436 in the lower left.
- That frame came from 5 × 5-minute exposures per colour (1 hour 15 minutes), so a short run already records the cluster.
- Best in September and October; it peaks near 81° altitude from 50°N.
Facts
- Size
- 6′
- Magnitude
- 8.8
- Coordinates
- RA 1h 16.0m, Dec +58° 49′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Sep, Oct
- Peak altitude
- 81° from 50°N, 66° from 35°N