M29 — Cooling Tower
Open Cluster in Cygnus
About
A small, bright open cluster in Cygnus, about 5,240 light-years away and about 1.7° south of Sadr. It is nicknamed the Cooling Tower. Dust along the line of sight dims its light, which makes its distance uncertain.
Imaging tips
- Only about 7′ across: needs a long focal length, about 3,460–5,770 mm on APS-C.
- Haze of Hα gas and dark dust clouds surround it in the Sadr region; one imager found the nebulosity made noise-reduction masks hard to build.
- Short subs are enough: 30 s unguided at a Bortle 5 site, and 180 s subs through a dual-band filter, both reported as workable; the nebulosity only appeared after stacking.
- Wide framing is tempting here, as the Crescent Nebula is nearby. High overhead in summer, up to about 78° from 50°N.
Facts
- Size
- 7′
- Magnitude
- 6.6
- Coordinates
- RA 20h 23.8m, Dec +38° 29′
- Framing, APS-C
- 3460–5770 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jul, Aug
- Peak altitude
- 79° from 50°N, 87° from 35°N