M71
Globular Cluster in Sagitta
About
NGC 6838, a globular cluster in Sagitta about 13,000 light-years away, sometimes called the Angelfish Cluster. Until the 1970s astronomers classed it as a dense open cluster because it is so loosely packed. It contains the irregular variable star Z Sagittae.
Imaging tips
- About 7′ across, so 3,460–5,770 mm on APS-C; too small for full frame, so use a long focal length.
- Easy and quick: one pair of imagers used 30 minutes of 30 s subs with a one-shot colour camera, even under a full Moon at a Bortle 5 site.
- Broadband only; at 21.1 mag/arcsec² it is not faint, and the Galactic Hunter authors call it an easy, quick target.
- Best around July and August.
Facts
- Size
- 7′
- Magnitude
- 8.2
- Coordinates
- RA 19h 53.8m, Dec +18° 47′
- Framing, APS-C
- 3460–5770 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jul, Aug
- Peak altitude
- 59° from 50°N, 74° from 35°N