Planetary Nebula · Cetus

C56 Skull Nebula

Magnitude
8
Season
Autumn
Difficulty
Hard
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Imaging reference
Skull Nebula (C56) Planetary Nebula

Observer's guide

About Skull Nebula

Skull Nebula (C56) is catalogued as a planetary nebula in Cetus. Its J2000 position is RA 00:47:03, Dec -11:52:18, corresponding to 11.7639 degrees RA and -11.8719 degrees Dec. The local catalogue places it about 1,600 light-years away. Its referenced angular extent is approximately 3.73 by 3.73 arcminutes.

Observing tips

StarWatchr rates this as a hard target at magnitude 8. It is associated with autumn observing, with midnight placement typically strongest around September. From 52 degrees north its theoretical meridian altitude is about 26.1 degrees; local horizons and the live altitude chart determine the practical window.

A small telescope under reasonably dark skies is a good starting point; use the live altitude chart to choose its highest point.

What to expect

The SIMBAD classification for the matched source is PN. A published radial velocity value is -15.7 km/s. The SIMBAD record currently connects it to 492 bibliographic references.

At roughly 3.7 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 3.73 by 3.73 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.

Sourced catalogue data

Scientific record

Measurements for C56 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 11.763925° · Dec -11.871936°
SIMBAD classification
PN
Spectral type
PG1159
Angular extent
3.73′ × 3.73′
Position angle
90°
Surface brightness
19.49 mag/arcsec²
Radial velocity
-15.7 km/s
Redshift
-0.00005237
Linked bibliography
492 references
Best midnight placement
September
Observable latitude range
-90° to 78.1°

Source: SIMBAD astronomical database (CDS, Strasbourg) (ODbL; checked 2026-08-09). Catalogue values may change when new measurements are published.

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