Spiral Galaxy · Canes Venatici

M51 Whirlpool Galaxy

Magnitude
8.4
Season
Spring
Difficulty
Moderate
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Imaging reference
Whirlpool Galaxy (M51) Spiral Galaxy

Observer's guide

About Whirlpool Galaxy

Whirlpool Galaxy (M51) is catalogued as a spiral galaxy in Canes Venatici. Its J2000 position is RA 13:29:52.71, Dec +47:11:42.6, corresponding to 202.4696 degrees RA and 47.1953 degrees Dec. The local catalogue places it about 37,000,000 light-years away. Its referenced angular extent is approximately 9.04 by 7.78 arcminutes.

Observing tips

StarWatchr rates this as a moderate target at magnitude 8.4. It is associated with spring observing, with midnight placement typically strongest around April. From 52 degrees north its theoretical meridian altitude is about 85.2 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 Sy2. SIMBAD records the morphology as SA. A published radial velocity value is 522.5 km/s. The SIMBAD record currently connects it to 4597 bibliographic references.

At roughly 9 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 9.04 by 7.78 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 M51 are kept separate from practical observing guidance.

Coordinates (J2000/ICRS)
RA 202.469575° · Dec 47.195258°
SIMBAD classification
Sy2
Morphology
SA
Angular extent
9.04′ × 7.78′
Position angle
28°
Surface brightness
21.65 mag/arcsec²
Radial velocity
522.54 km/s
Redshift
0.00174454
Linked bibliography
4,597 references
Best midnight placement
April
Observable latitude range
-42.8° 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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