B150 — Seahorse Nebula
Dark Nebula in Cepheus
About
The Seahorse, a long thin dark nebula in Cepheus about 1,200 light-years away. It is built from three dense gas cores, labelled L1082 A, B and C, which are described as star-forming regions.
Imaging tips
- It runs roughly 1° but is never more than about 3′ wide, so 400–670 mm on APS-C (620–1030 mm full frame) fits the whole length.
- A dark nebula shows only against the stars behind it, so shoot broadband.
- One imager used LRGB with 36 min of luminance and 50 min per colour, and noted a strong light gradient and changing transparency; another gathered 408 min of luminance and 264 min of colour.
- B149 and B148 lie nearby, slightly to the north; B149 is 43′ away, so a wider field is needed to include it.
- Best in July and August; it peaks near 80° altitude from 50°N.
Facts
- Size
- 60′ × 20′
- Magnitude
- —
- Coordinates
- RA 20h 51.1m, Dec +60° 11′
- Framing, APS-C
- 400–670 mm
- Framing, full frame
- 620–1030 mm
- Best months
- Jul, Aug
- Peak altitude
- 80° from 50°N, 65° from 35°N
Nearby
- B149 · 43.0′ away