Whirlpool Galaxy
M 51
Scientific overview
Whirlpool Galaxy is a barred spiral galaxy in the constellation Canes Venatici. It shines at apparent magnitude 8.36 and spans about 13.71 arcminutes of sky.
Observation guide
Guidance follows standard observing practice, derived from the object's real magnitude and position. A dark, moonless sky always helps.
Location in the sky
Precision measurements
Distances and velocities from SIMBAD and redshift from NED · M 51
| Distance | 2.6093e+7 ly | SIMBAD · catalogued |
| Physical size (major axis) | 104,059 ly | SIMBAD · derived |
| Physical size (minor axis) | 88,575 ly | SIMBAD · derived |
| Redshift (z) | 0.002 | NED · catalogued |
| Radial velocity | 522.543803 km/s | SIMBAD · measured |
| Right ascension (ICRS) | 202.469575 deg | SIMBAD · measured |
| Declination (ICRS) | 47.195258 deg | SIMBAD · measured |
Full field-level provenance
- Distance: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · mesDistance · dist · 2011ApJS..192....6L · distance indicator: T-F · catalogued value · source value 8 Mpc · retrieved 2026-07-11
- Physical size (major axis): Centre de données astronomiques de Strasbourg (CDS) · derived (OpenNGC angular size × SIMBAD distance) · physical size = angular size × distance (small-angle); angular size from OpenNGC, distance from SIMBAD mesDistance · derived · retrieved 2026-07-11
- Physical size (minor axis): Centre de données astronomiques de Strasbourg (CDS) · derived (OpenNGC angular size × SIMBAD distance) · physical size = angular size × distance (small-angle); angular size from OpenNGC, distance from SIMBAD mesDistance · derived · retrieved 2026-07-11
- Redshift (z): NASA/IPAC Extragalactic Database · NED · ObjectLookup · Redshift · 2024MNRAS.532.4106V · catalogued value · NED quality SLS · retrieved 2026-07-11
- Radial velocity: Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · rvz_radvel · 2022ApJS..261....6K · direct catalogue measurement · retrieved 2026-07-11
- Right ascension (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · ra · 2006AJ....131.1163S · direct catalogue measurement · retrieved 2026-07-11
- Declination (ICRS): Centre de données astronomiques de Strasbourg (CDS) · SIMBAD · basic · dec · 2006AJ....131.1163S · direct catalogue measurement · retrieved 2026-07-11
Physical size is derived from the OpenNGC angular size and the catalogued distance (small-angle: size = angle × distance). Redshift is the object's measured redshift — a negative value is a blueshift (the galaxy is approaching, its motion dominated by local rather than cosmic expansion). Fields a source did not provide are omitted, never invented.
Other objects in Canes Venatici
| Object | Type | Mag | Size (′) |
|---|---|---|---|
| M 3M 3 · NGC 5272 | Globular cluster | 6.39 | 16.2 |
| M 94M 94 · NGC 4736 | Barred spiral galaxy | 8.24 | 7.74 |
| Sunflower GalaxyM 63 · NGC 5055 | Spiral galaxy | 8.61 | 11.83 |
| Whale GalaxyC 32 · NGC 4631 | Barred spiral galaxy | 9.24 | 14.45 |
| M 106M 106 · NGC 4258 | Spiral galaxy | 9.29 | 16.98 |
| NGC 5195NGC 5195 | Barred spiral galaxy | 9.58 | 5.5 |
| NGC 4449C 21 · NGC 4449 | Irregular galaxy | 9.64 | 4.66 |
| NGC 4490NGC 4490 | Barred spiral galaxy | 9.72 | 6.71 |
Sources
The primary and reference sources this topic draws on.
- OpenNGCOpenNGC (M. Verga) — NGC/IC, Messier, and Caldwell catalogue data
Openly-licensed deep-sky catalogue: object types, positions, magnitudes, sizes, morphology, and cross-identifiers.