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Fireworks Galaxy (NGC 6946)
spiral galaxy in Cepheus
The Fireworks Galaxy is a face-on spiral on the border of Cepheus and Cygnus that has hosted around ten recorded supernovae. It lies behind the dusty Milky Way, so the field is dense with foreground stars and the galaxy is dimmed by dust.
Save your telescope or lens on the planner to lay your camera frame over this diagram.
// Key facts
- Catalog
- NGC 6946
- Type
- spiral galaxy
- Constellation
- Cepheus
- Size
- 11′ across
- Brightness
- Magnitude 8.9
- Distance
- about 25 million light-years
- Peak month (any location)
- Jul
- Typical prime months
- May to Oct
- Difficulty
- Advanced
- Filter
- No filter (broadband); a light-pollution filter is optional
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How to image Fireworks Galaxy
- A nearby open cluster, NGC 6939, fits in a frame of about 1 degree.
- Foreground dust and stars make it hard, so a dark sky and long exposure are needed.
- It is high in the sky from northern sites in autumn.
Framing: what focal length?
NGC 6946 is small, so a "60% of the frame" focal length would be impractical. Here is how much of an APS-C frame it covers at common long focal lengths; expect to crop.
| Focal length | Share of the frame width |
|---|---|
| 1,000 mm | about 14% |
| 2,000 mm | about 27% |
| 3,000 mm | about 41% |
How high does it climb from your latitude?
The highest point NGC 6946 reaches in the sky. Above about 60° is excellent, 30° to 60° is workable, and under 30° you are looking through a lot of air.
| Latitude | Highest point | Rating |
|---|---|---|
| 55°N (Scotland, Alaska) | 85° | High in the sky |
| 45°N (Minneapolis, Milan) | 75° | High in the sky |
| 35°N (Los Angeles, Tokyo) | 65° | High in the sky |
| 25°N (Miami, Cairo) | 55° | Workable |
| 35°S (Sydney, Santiago) | below horizon | Never rises |
Also worth imaging
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