Galaxy · Cassiopeia

C17 NGC 147

Magnitude
9.5
Season
Autumn
Difficulty
Hard
Star-hop chart
C170.0° field0° rotation
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Imaging reference
NGC 147 (C17) Galaxy

Observer's guide

About NGC 147

NGC 147 (C17) is catalogued as a galaxy in Cassiopeia. Its J2000 position is RA 00:33:12, Dec +48:30:36, corresponding to 8.3005 degrees RA and 48.5087 degrees Dec. The local catalogue places it about 2,300,000 light-years away. Its referenced angular extent is approximately 12.59 by 7.08 arcminutes.

Observing tips

StarWatchr rates this as a hard target at magnitude 9.5. It is associated with autumn observing, with midnight placement typically strongest around September. From 52 degrees north its theoretical meridian altitude is about 86.5 degrees; local horizons and the live altitude chart determine the practical window.

Because it is faint, use a larger aperture where possible, avoid bright Moon conditions, and use averted vision.

What to expect

The SIMBAD classification for the matched source is GiG. SIMBAD records the morphology as dGspD.... A published radial velocity value is -193.1 km/s. The SIMBAD record currently connects it to 721 bibliographic references.

At roughly 12.6 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 12.59 by 7.08 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 C17 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 8.3005° · Dec 48.508739°
SIMBAD classification
GiG
Morphology
dGspD...
Angular extent
12.59′ × 7.08′
Position angle
25°
Surface brightness
23.0 mag/arcsec²
Radial velocity
-193.1 km/s
Redshift
-0.0006439
Linked bibliography
721 references
Best midnight placement
September
Observable latitude range
-41.5° to 90°

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

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