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Leo Triplet (M66)
spiral galaxy in Leo
M66 is the brightest of the Leo Triplet, a spiral galaxy with a distorted outline that shows signs of gravitational interaction with its neighbors. It is brighter than M65 and has a stronger core.
Save your telescope or lens on the planner to lay your camera frame over this diagram.
// Key facts
- Catalog
- M66
- Type
- spiral galaxy
- Constellation
- Leo
- Size
- 9′ across
- Brightness
- Magnitude 8.9
- Distance
- about 36 million light-years
- Peak month (any location)
- Mar
- Typical prime months
- Dec to May
- Difficulty
- Intermediate
- Filter
- No filter (broadband); a light-pollution filter is optional
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How to image Leo Triplet
- Frame the triplet together with about 700 to 800 mm on APS-C.
- Long exposures reveal dust lanes and the tidal distortion.
- Best in spring evenings from northern sites.
Framing: what focal length?
M66 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 11% |
| 2,000 mm | about 22% |
| 3,000 mm | about 33% |
How high does it climb from your latitude?
The highest point M66 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) | 48° | Workable |
| 45°N (Minneapolis, Milan) | 58° | Workable |
| 35°N (Los Angeles, Tokyo) | 68° | High in the sky |
| 25°N (Miami, Cairo) | 78° | High in the sky |
| 35°S (Sydney, Santiago) | 42° | Workable |
Also worth imaging
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