M14
Globular Cluster in Ophiuchus
About
A globular cluster in Ophiuchus, about 30,300 light-years away and roughly 100 light-years across, with a visibly stretched outline. A nova erupted in it in 1938; nobody noticed until 1964, when astronomers went back through old photographic plates.
Imaging tips
- About 11′ across, so it needs a long focal length: 2,200–3,670 mm on APS-C (3,380–5,630 mm on full frame).
- One guide advises 30 to 60 second subs and skipping filters, since there is no nebulosity; about 3 hours gave a good result, and dozens of hours would reveal fainter surroundings.
- Seeing matters: one imager lost two nights to blobby stars after a cold front, and then blended 8-, 5- and 1-minute exposures to hold the core.
- At 21.4 mag/arcsec² the outer stars need more integration than the core does.
- Best in June; it stays below 37° altitude from 50°N.
Facts
- Size
- 11′
- Magnitude
- 7.6
- Coordinates
- RA 17h 37.6m, Dec −3° 15′
- Framing, APS-C
- 2200–3670 mm
- Framing, full frame
- 3380–5630 mm
- Best months
- Jun
- Peak altitude
- 37° from 50°N, 52° from 35°N