H-NGC654
Open Cluster in Cassiopeia
About
A young open cluster in Cassiopeia nicknamed the Fuzzy Butterfly, about 7,830 light-years away and an estimated 14 to 15 million years old. It has around 80 members, three of them Be stars, plus a yellowish supergiant that may belong to it. It is thought to be part of the Cassiopeia OB8 association, which also contains M103.
Imaging tips
- At about 5–6′ it is too small to frame alone: use a long focal length and a fine pixel scale, or go wide and treat it as one cluster among several.
- NGC 663 lies roughly 44′ away and NGC 659 about 1.2° away (approximate); one imager caught all three in a single RGB frame on a 120 mm refractor with a 0.7× reducer.
- One imager framed ten Cassiopeia clusters, this one included, in broadband LRGB over several nights in December.
- Dust in front of the cluster reddens it unevenly, less toward the centre, so star colours differ across the field.
- Best in October and November; it peaks near 78° from 50°N.
Facts
- Size
- 5′
- Magnitude
- 6.5
- Coordinates
- RA 1h 44.0m, Dec +61° 53′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Oct, Nov
- Peak altitude
- 78° from 50°N, 63° from 35°N