C56
Planetary Nebula in Cetus
About
NGC 246, the Skull Nebula, lies in Cetus roughly 3,500 light-years from us. Three stars sit at its heart, which no other known planetary nebula can claim. Herschel discovered it in 1785.
Imaging tips
- About 4′ across, so it is too small to frame: use a long focal length and a fine pixel scale.
- Faint for its size at 22.6 mag/arcsec², so plan many hours; one broadband LRGB image reached 22 hours.
- A modified DSLR with no filter and only 8 × 300 s already records the nebula, so a first look needs little time.
- Best in September and October; it stays below 28° altitude from 50°N.
Facts
- Size
- 4.1′
- Magnitude
- 10.9
- Coordinates
- RA 0h 47.0m, Dec −11° 52′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Sep, Oct
- Peak altitude
- 28° from 50°N, 43° from 35°N