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Silver Sliver Galaxy (NGC 891)
spiral galaxy in Andromeda
NGC 891 is a classic edge-on spiral galaxy in Andromeda, crossed by a dark dust lane along its whole length. It is thought to resemble the Milky Way as we would see it from the side.
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// Key facts
- Catalog
- NGC 891
- Type
- spiral galaxy
- Constellation
- Andromeda
- Size
- 14′ across
- Brightness
- Magnitude 10
- Distance
- about 30 million light-years
- Peak month (any location)
- Oct
- Typical prime months
- Aug to Jan
- Difficulty
- Intermediate
- Filter
- No filter (broadband); a light-pollution filter is optional
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How to image Silver Sliver Galaxy
- At 14 arcminutes, use 1,000 to 1,500 mm to show the dust lane.
- It has low surface brightness, so a dark sky and long exposure help.
- High in the sky on autumn evenings from northern sites.
Framing: what focal length?
NGC 891 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 17% |
| 2,000 mm | about 35% |
| 3,000 mm | about 52% |
How high does it climb from your latitude?
The highest point NGC 891 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) | 77° | High in the sky |
| 45°N (Minneapolis, Milan) | 87° | High in the sky |
| 35°N (Los Angeles, Tokyo) | 83° | High in the sky |
| 25°N (Miami, Cairo) | 73° | High in the sky |
| 35°S (Sydney, Santiago) | 13° | Stays low |
Also worth imaging
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