C91
Open Cluster in Carina
About
A bright open cluster in Carina, about 1,320 light-years away, nicknamed the Wishing Well. Roughly 150 of its stars are 7th magnitude or dimmer, among them red giants and white dwarfs. Hubble pointed at it first in May 1990.
Imaging tips
- The cluster is about 50′ across, so it needs a wide field; one image with a TMB 92 SS refractor at f/5.5 framed 2° × 1.36° around it.
- Two planetary nebulae sit near one corner of a wide frame: PHR 1107-5857 and PHR 1107-5855.
- Faint hydrogen nebulosity around it showed up well in Hα in a 2011 LHaRGB image, even under a bright Moon.
- It is bright enough for short sessions: one RGB result came from 40 frames of 120 s, about 1.3 hours.
- Best in February and March, but it never rises from 50°N and peaks near −4° from 35°N, so it never rises there either.
Facts
- Size
- 50′
- Magnitude
- 3.0
- Coordinates
- RA 11h 5.6m, Dec −58° 42′
- Framing, APS-C
- 480–810 mm
- Framing, full frame
- 740–1240 mm
- Best months
- Feb, Mar
- Peak altitude
- never rises from 50°N, never rises from 35°N