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
This is rated 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.