Cr89
Open Cluster in Gemini
About
A faint open cluster in Gemini, lying north of Tejat Posterior and Tejat Prior (μ and η Geminorum) and forming a nearly equilateral triangle with them. In binoculars five of its stars stand out as a shape one guide compares to a horizontal Christmas tree; the rest are faint.
Imaging tips
- At 810–1,350 mm on APS-C (1,240–2,060 mm full frame) the 30′ cluster fills a good part of the frame.
- Faint at 23.1 mag/arcsec², so plan many hours of broadband data. An observing guide also notes it is hard to tell apart from its surroundings.
- Best in December and January; it peaks near 64° altitude from 50°N.
Facts
- Size
- 30′
- Magnitude
- 7.1
- Coordinates
- RA 6h 18.0m, Dec +23° 38′
- Framing, APS-C
- 810–1350 mm
- Framing, full frame
- 1240–2060 mm
- Best months
- Jan, Dec
- Peak altitude
- 64° from 50°N, 79° from 35°N