M72
Globular Cluster in Aquarius
About
NGC 6981, a globular cluster in Aquarius about 54,500 light-years away. Pierre Méchain found it on 29 August 1780, and 43 variable stars are known in it.
Imaging tips
- About 6′ across, so too small to frame: use a long focal length and a fine pixel scale.
- Galactic Hunter's author keeps subs of a minute or less for a sharp cluster, and goes to several minutes only when chasing the dust behind it.
- That author spent 10 hours of 300 s subs at f/2 under Bortle 2 skies to look for faint integrated flux nebula; a single sub showed none.
- M73 lies about 1.5° east, well outside a 13′ field, so getting both needs a wide lens or a mosaic.
- Best around July and August; it stays below 28° altitude from 50°N.
Facts
- Size
- 6′
- Magnitude
- 9.3
- Coordinates
- RA 20h 53.5m, Dec −12° 32′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jul, Aug
- Peak altitude
- 28° from 50°N, 43° from 35°N