Go / no go for deep skyGo / no go for deep sky imaging
M30
globular cluster in Capricornus
M30 is a compact globular cluster in Capricornus, with a dense, core-collapsed center and a long trailing stream of stars to one side. It is a fairly small target, best treated as a close-up.
Save your telescope or lens on the planner to lay your camera frame over this diagram.
// Key facts
- Catalog
- M30
- Type
- globular cluster
- Constellation
- Capricornus
- Size
- 11′ across
- Brightness
- Magnitude 7.7
- Distance
- about 28,000 light-years
- Peak month (any location)
- Aug
- Typical prime months
- Jun to Oct
- Difficulty
- Intermediate
- Filter
- No filter (broadband)
Pick a saved location or share your device location. Your coordinates are used only to calculate tonight and are not stored. To save locations, use the planner.
How to image M30
- At 11 arcminutes, 1,000 mm or more suits it best.
- Capricornus is in the southern part of the autumn sky, so it is low from northern latitudes.
- Blend short exposures to keep the dense core resolved.
Framing: what focal length?
M30 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 M30 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) | 12° | Stays low |
| 45°N (Minneapolis, Milan) | 22° | Stays low |
| 35°N (Los Angeles, Tokyo) | 32° | Workable |
| 25°N (Miami, Cairo) | 42° | Workable |
| 35°S (Sydney, Santiago) | 78° | High in the sky |
Also worth imaging
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