Sh2-276 — Barnard's Loop
HII Region in Orion
About
A huge, faint arc of glowing hydrogen in Orion, roughly 1,400 light-years away and centred between the Horsehead and Orion Nebula. It is thought to be what a supernova left behind some 2 million years back, and sources give its span as 10° to 14°.
Imaging tips
- It spans many degrees, so it needs a wide lens rather than a telescope. One imager shot it with a 50 mm lens; another used 24 × 5 min at ISO 800 on a 50 mm lens.
- Hα carries it. One imager spent 7.2 hours on it with a 12 nm Hα clip-on filter, half of it Hα and half RGB, in 6 min subs on an unmodified DSLR.
- That imager advises putting the largest share of the night into the red signal; longer integration also brought out the fainter outer gas.
- A wide frame also takes in M42, M43, the Running Man, the Horsehead, the Flame and M78.
- Best around November and December; it stays below about 36° altitude from 50°N.
Facts
- Size
- 600′
- Magnitude
- —
- Coordinates
- RA 5h 29.0m, Dec −4° 17′
- Framing, APS-C
- 40–70 mm
- Framing, full frame
- 60–100 mm
- Best months
- Nov, Dec
- Peak altitude
- 36° from 50°N, 51° from 35°N
Nearby
- Sh2-279 (Running Man Nebula) · 98.9′ away
- M43 (De Mairan's Nebula) · 114.2′ away
- M42 (Orion Nebula) · 115.3′ away
- vdB46 · 183.4′ away
- B33 (Horsehead Nebula) · 209.7′ away
- Cr70 (Orion Belt) · 214.6′ away
- vdB52 · 224.9′ away
- H-NGC1788 · 335.3′ away
- M78 (Casper the Friendly Ghost Nebula) · 373.3′ away
- vdB49 · 526.9′ away