Sh2-273 — Cone Nebula Region
HII Region in Monoceros
About
A large emission region in Monoceros, about 2,600 to 2,700 light-years away, that takes in the whole NGC 2264 complex. The Christmas Tree Cluster forms its northern part and the Cone Nebula its southern part, with the variable star S Monocerotis near the centre.
Imaging tips
- Sources give about 140′ for the whole region, so it is far wider than the Cone alone; a tight framing on the Cone leaves out most of the surrounding nebulosity.
- Red hydrogen glow, so an Hα or dual-band filter suits it. One imager used a 135 mm lens with a light-pollution filter and 16 × 6 min exposures to cover about 10° × 6.7°.
- That wide field showed the reddish nebulosity filling almost the frame and reaching about 6° south toward the Rosette Nebula, and B38 and B39, two dark clouds, to the northwest.
- Best around December and January; it peaks near 50° altitude from 50°N.
Facts
- Size
- 250′
- Magnitude
- —
- Coordinates
- RA 6h 40.9m, Dec +9° 53′
- Framing, APS-C
- 100–160 mm
- Framing, full frame
- 150–250 mm
- Best months
- Jan, Dec
- Peak altitude
- 50° from 50°N, 65° from 35°N