Emission Nebula · Cygnus

C27 Crescent Nebula

Magnitude
7.4
Season
Summer
Difficulty
Hard
Star-hop chart
C270.0° field0° rotation
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Imaging reference
Crescent Nebula (C27) Emission Nebula

Observer's guide

About Crescent Nebula

Crescent Nebula (C27) is catalogued as an emission nebula in Cygnus. Its J2000 position is RA 20:12:07, Dec +38:21:18, corresponding to 303.0273 degrees RA and 38.3549 degrees Dec. The local catalogue places it about 4,700 light-years away. No consistent angular diameter is available in the source record.

Observing tips

StarWatchr rates this as a hard target at magnitude 7.4. It is associated with summer observing, with midnight placement typically strongest around July. From 52 degrees north its theoretical meridian altitude is about 76.4 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 WR*. A published radial velocity value is -100 km/s. The SIMBAD record currently connects it to 718 bibliographic references.

Confirm the framing in the live sky atlas before choosing a field of view. Use the listed unknown 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 C27 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 303.027258° · Dec 38.35494°
SIMBAD classification
WR*
Spectral type
WN6(h)-s
Radial velocity
-100 km/s
Redshift
-0.00033351
Linked bibliography
718 references
Best midnight placement
July
Observable latitude range
-51.6° 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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24-hour altitude profile

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