Go / no go for deep skyGo / no go for deep sky imaging
M35
open cluster in Gemini
M35 is a large, rich open cluster in Gemini, with a smaller, more distant cluster, NGC 2158, sitting right beside it. The two make a pleasing pair of different ages and distances in one frame.
Save your telescope or lens on the planner to lay your camera frame over this diagram.
// Key facts
- Catalog
- M35
- Type
- open cluster
- Constellation
- Gemini
- Size
- 28′ across
- Brightness
- Magnitude 5.1
- Distance
- about 2,800 light-years
- Peak month (any location)
- Dec
- Typical prime months
- Oct to Mar
- Difficulty
- Beginner
- Filter
- No filter (broadband)
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How to image M35
- At 28 arcminutes, 400 to 700 mm gives you room for NGC 2158 in the same frame.
- Short exposures keep the bright stars from blooming.
- Gemini is well placed on winter evenings from the northern hemisphere.
Framing: what focal length?
The focal length at which M35 spans about 60% of the long side of the sensor, leaving room around it. Treat it as a starting point; the right framing is a matter of taste.
| Sensor | Focal length |
|---|---|
| 1-inch sensor (13.2 mm) | about 970 mm |
| APS-C (23.5 mm) | about 1730 mm |
| Full frame (36 mm) | about 2650 mm |
How high does it climb from your latitude?
The highest point M35 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) | 59° | Workable |
| 45°N (Minneapolis, Milan) | 69° | High in the sky |
| 35°N (Los Angeles, Tokyo) | 79° | High in the sky |
| 25°N (Miami, Cairo) | 89° | High in the sky |
| 35°S (Sydney, Santiago) | 31° | Workable |
Also worth imaging
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