Sh2-254
HII Region in Orion
About
The most extensive of a group of hydrogen clouds in Orion, about 8,000 light-years away. Sh2-255 and Sh2-257 lie close beside it on the sky and are the brighter two.
Imaging tips
- Only about 8′ across, so it needs a long focal length: 3030–5050 mm on APS-C.
- One imager framed the group in a field of about 66′ × 47′, taking in Sh2-254 with its brighter neighbours.
- Hα is the usual choice for an emission nebula. One imager gave 2.5 hours (5 × 30 min, 10 nm filter) and still found the group weak; another used 9 hours 20 minutes, mostly Hα.
- Best in December and January; it peaks near 58° altitude from 50°N.
Facts
- Size
- 8′
- Magnitude
- —
- Coordinates
- RA 6h 12.0m, Dec +18° 3′
- Framing, APS-C
- 3030–5050 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jan, Dec
- Peak altitude
- 58° from 50°N, 73° from 35°N