C99 — Coalsack Nebula
Dark Nebula in Crux
About
The Coalsack, a dark nebula in Crux about 590 light-years away, seen as a dark patch against the southern Milky Way. It is close to Acrux and spans about 7° by 5°. In Australian Aboriginal astronomy it forms the head of the emu in the sky.
Imaging tips
- Very large: at 60–100 mm on APS-C the nebula fills a third to half of the frame, and it exceeds a typical frame at longer lenses, so use a wide lens or a mosaic.
- A dark nebula shows only against the background stars of the Milky Way, so broadband (RGB or luminance) is the choice.
- The Jewel Box cluster lies about 3.7° away, within a wide frame.
- Best in March and April, but it never rises from mid-northern latitudes such as 35°N or 50°N: a southern-hemisphere target.
Facts
- Size
- 420′ × 300′
- Magnitude
- —
- Coordinates
- RA 12h 32.0m, Dec −63° 0′
- Framing, APS-C
- 60–100 mm
- Framing, full frame
- 90–150 mm
- Best months
- Mar, Apr
- Peak altitude
- never rises from 50°N, never rises from 35°N