Sh2-171
HII Region in Cepheus
About
The emission-nebula part of NGC 7822, a star-forming complex in Cepheus, only a few million years old at most and roughly 2,900 light-years away, that also holds the cluster Berkeley 59. An O5-type eclipsing binary, BD+66 1673, helps light the gas and carves its elephant-trunk pillars.
Imaging tips
- Wikipedia gives the whole complex as about 100′ across, so plan a wide field for it.
- Hα carries the structure: one imager spent 131 twenty-minute Hα frames plus 16 ten-minute frames each of R, G and B, about 51 hours 40 minutes.
- That imager also posted the Hα channel on its own.
- Sh2-170 lies about 2.8° away, so framing both needs a very wide field or two panels.
- Best in September and October; it peaks near 73° altitude from 50°N.
Facts
- Size
- 180′
- Magnitude
- —
- Coordinates
- RA 0h 1.1m, Dec +67° 25′
- Framing, APS-C
- 130–220 mm
- Framing, full frame
- 210–340 mm
- Best months
- Sep, Oct
- Peak altitude
- 73° from 50°N, 58° from 35°N
Nearby
- Sh2-170 (Little Rosette) · 167.1′ away