H-NGC6229
Globular Cluster in Hercules
About
A small globular cluster in Hercules, about 100,000 light-years away, roughly four times farther than its famous neighbour M13. William Herschel found it in 1787 and at first took it for a planetary nebula. Its stars come from two distinct generations.
Imaging tips
- About 5′ across, so it is too small to frame: use a long focal length and a fine pixel scale.
- Faint at 21.5 mag/arcsec² and described by one observer as small and faint, so plan a generous amount of broadband data.
- Two 8th-magnitude stars lie just west of the cluster, which one observer used to locate it.
- One imager used 30 × 120 s at f/10 through a skyglow filter from a red-zone site.
- Best around May and June; it peaks near 88° altitude from 50°N.
Facts
- Size
- 5′
- Magnitude
- 9.4
- Coordinates
- RA 16h 47.0m, Dec +47° 32′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- May, Jun
- Peak altitude
- 88° from 50°N, 78° from 35°N