M107
Globular Cluster in Ophiuchus
About
A very loose globular cluster in Ophiuchus, about 20,900 light-years away and 30 light-years in radius by one listing. Méchain found it in 1782, and it was added to the Messier catalogue only in 1947. It holds 22 known RR Lyrae variable stars.
Imaging tips
- Around 10–13′ across by different sources: 2,420–4,040 mm on APS-C, or 3,710–6,190 mm on full frame.
- One imager shot 1 hour of 1-minute subs and found the loose cluster easier to process than most, advising care not to blow out the core; they say a Bortle 4 or darker sky usually suffices.
- Another gathered 3 hours through RGB filters in 5-minute subs, 60 minutes per channel; a globular has no nebulosity, so broadband is the right choice.
- It stays low, below 27° altitude from 50°N, so pick a clear southern horizon. Best around May and June.
Facts
- Size
- 10′
- Magnitude
- 7.9
- Coordinates
- RA 16h 32.5m, Dec −13° 3′
- Framing, APS-C
- 2420–4040 mm
- Framing, full frame
- 3710–6190 mm
- Best months
- May, Jun
- Peak altitude
- 27° from 50°N, 42° from 35°N