C10
Open Cluster in Cassiopeia
About
NGC 663, a young open cluster in Cassiopeia, roughly 6,500 to 8,800 light-years away depending on the source. It is only 20 to 25 million years old and holds an unusually large number of Be stars, about 24 so far.
Imaging tips
- A molecular cloud behind the cluster blocks the stars beyond it, which leaves the cluster sharply set off from a sparse surrounding field.
- Short subs work: one imager stacked 64 × 15 s unguided with a one-shot colour camera and a light-pollution filter.
- Another image used LRGB with about 20 frames of 3 min per channel, so a modest total can be enough for a cluster.
- M103, NGC 654 and NGC 659 belong to the same stellar association, so a wider field can pick up neighbours.
- Best in October and November; it peaks near 79° altitude from 50°N.
Facts
- Size
- 15′
- Magnitude
- 7.1
- Coordinates
- RA 1h 46.4m, Dec +61° 13′
- Framing, APS-C
- 1620–2690 mm
- Framing, full frame
- 2480–4130 mm
- Best months
- Oct, Nov
- Peak altitude
- 79° from 50°N, 64° from 35°N