C13 — Owl Cluster
Open Cluster in Cassiopeia
About
An open cluster in Cassiopeia, some 7,900 light-years from us and about 21 million years old. Its owl or E.T. look comes from a pair of brighter stars, Phi Cassiopeiae and HD 7902, that read as eyes against the rest.
Imaging tips
- About 14–20′ across: 1,730–2,890 mm on APS-C frames it snugly, and a shorter lens shows the whole cluster with room around it.
- One imager made a clean colour image from only 1 hour of 5-minute R, G and B subs, so a short session already works.
- A wider frame also takes in the older cluster NGC 436, about 9,800 light-years away, plus a few very faint galaxies.
- Best in September and October; it peaks near 82° altitude from 50°N.
Facts
- Size
- 14′
- Magnitude
- 6.4
- Coordinates
- RA 1h 19.6m, Dec +58° 17′
- Framing, APS-C
- 1730–2890 mm
- Framing, full frame
- 2650–4420 mm
- Best months
- Sep, Oct
- Peak altitude
- 82° from 50°N, 67° from 35°N