Cr359
Open Cluster in Ophiuchus
About
A very loose open cluster in Ophiuchus, also listed as Melotte 186, spread over roughly 3 to 4° of sky. Distance estimates range from about 650 to about 1,470 light-years, depending on which stars count as members. Collinder noted only 15 stars in it in 1931.
Imaging tips
- Sources give its size as 187–240′, several degrees across, so it needs a short lens or a mosaic rather than a telescope frame.
- One imager shot it at 85 mm on a full-frame camera with eight 1-minute exposures, using a V-shaped star pattern about 4° east of Beta Ophiuchi as the guide.
- It is a sparse star cluster, so broadband is the filter choice.
- Best around June and July; it peaks near 43° from 50°N.
Facts
- Size
- 240′
- Magnitude
- 3.0
- Coordinates
- RA 18h 2.4m, Dec +3° 16′
- Framing, APS-C
- 100–170 mm
- Framing, full frame
- 150–260 mm
- Best months
- Jun, Jul
- Peak altitude
- 43° from 50°N, 58° from 35°N
Nearby
- Cr350 · 238.8′ away