B163
Dark Nebula in Cepheus
About
A small dark nebula in Cepheus, one of many dark clouds scattered through the large emission nebula IC 1396. One source puts it about 3,000 light-years away; Barnard himself called it small and very black.
Imaging tips
- Only about 8×5′, so it is too small to frame: use a long focal length, around 3030–5050 mm on APS-C.
- A dark nebula is seen only against the stars behind it, so shoot broadband. One imager made a clean image without any hydrogen-alpha data.
- One imager shot 9 × 10 min luminance and 4 × 10 min per colour, spread over many nights with varying conditions.
- The centre of IC 1396 and its Elephant Trunk lie a full degree away, and a small cometary globule appears in the corner of a tight frame.
- Best in July and August; it peaks near 83° altitude from 50°N.
Facts
- Size
- 8′ × 5′
- Magnitude
- —
- Coordinates
- RA 21h 42.2m, Dec +56° 44′
- Framing, APS-C
- 3030–5050 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Jul, Aug
- Peak altitude
- 83° from 50°N, 68° from 35°N