Black Eye Galaxy (Messier 64 / NGC 4826)
J2000 coordinates, TRGB distance (17.3 Mly), magnitude 8.52, dark absorbing dust hood, counter-rotating gas disk, and observing guide for Messier 64.
Provenance-Backed Scientific Measurements
Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.
| Parameter | Value | Uncertainty | Method & Epoch | Quality Status | Source Archive |
|---|---|---|---|---|---|
| Integrated visual magnitude (V) | 8.52 mag | ± 0.07 mag | Integrated CCD aperture photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Distance in light-years | 17300000 ly | ± 600000 ly | HST Tip of the Red Giant Branch (TRGB: 5.30 ± 0.18 Mpc) | definitive | SH0ES Local Distance Ladder Hubble Constant |
| Apparent major axis | 10.7 arcmin | ± 0.4 arcmin | Optical isophotal dimensions (10.7′ × 5.1′) | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric recession velocity | 408 km/s | ± 2 km/s | H I 21-cm and optical emission-line spectroscopy | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Black Eye Galaxy (Messier 64 / NGC 4826) at RA 12h 56m 43.69s, Dec +21° 40′ 57.6″ within Coma Berenices, alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.
Astrophysical Context & Structure
Independently discovered by Edward Pigott on March 23, 1779, Johann Elert Bode twelve days later, and Charles Messier in 1780, the Black Eye Galaxy (Messier 64, NGC 4826) is one of the most distinctive and nearest bright spiral galaxies in the northern sky at just 17.3 million light-years in Coma Berenices. William Herschel first coined its famous nickname after noticing an arcuate, coal-black dust cloud curving across the northeastern side of its brilliant nucleus like a bruised eye.
In the early 1990s radio and optical spectroscopists discovered the remarkable physical cause of M64's 'black eye': the galaxy possesses two concentric gas disks rotating in opposite directions! All of the stars in M64 and the inner gas disk (within a radius of 3,000 light-years) rotate clockwise, whereas the outer neutral-hydrogen gas disk extending out to 40,000 light-years rotates counterclockwise.
Roughly one billion years ago, M64 absorbed a gas-rich satellite galaxy on a retrograde orbit. Where the clockwise inner gas and counterclockwise outer gas collide along a shear boundary at ~3,000 light-years radius, supersonic shock waves compress molecular clouds into the opaque dust hood and ignite a fierce ring of knots of pink H II star formation.
Practical Visual Observing Guide
- Situated 1° east-northeast of the 5th-magnitude star 35 Comae Berenices and ~4.5° northwest of the globular cluster M53.
- The bright 8.5-magnitude oval disk is easy in 10×50 binoculars or any 60 mm scope.
- To clearly resolve the dark comma-shaped 'Black Eye' dust hood just northeast of the pinpoint nucleus, use a 150–200 mm telescope at high magnification (150×–220×) when M64 transits high overhead.
Catalog Cross-Identifications & Aliases
Common Aliases: M64 · NGC 4826 · UGC 8062 · Evil Eye Galaxy · Sleeping Beauty Galaxy
| Catalog Authority | Identifier |
|---|---|
| MESSIER | M 64 |
| NGC | NGC 4826 |
| SIMBAD | M 64 |
| WIKIDATA | Q13986 |
Related Objects, Comparisons & Guides
Sombrero Galaxy (Messier 104 / NGC 4594)
Coordinates, TRGB distance (9.55 Mpc / 31.1 Mly), edge-on dust lane, 1-billion-M☉ central black hole, and observing guide for M104.
Needle Galaxy (NGC 4565 Edge-On Spiral)
J2000 coordinates, TRGB distance (38.8 Mly), magnitude 9.56, 87-degree edge-on inclination, razor-sharp dust lane, and observing guide for NGC 4565.
Cat's Eye Galaxy (Messier 94 / NGC 4736)
J2000 coordinates, TRGB distance (15.0 Mly), magnitude 8.24, blazing inner starburst ring, outer pseudoring, and observing guide for Messier 94.
Surface Brightness & Extended Objects Guide
Why surface brightness (mag/arcsec²) governs nebula and galaxy visibility more than integrated magnitude, and how exit pupil controls eyepiece contrast.
Angular Size, Separation & Field of View
How angular diameter (degrees, arcminutes, arcseconds), spherical angular separation, and small-angle physical diameter relate to telescope field of view.
Scientific Sources & Dataset Provenance
- Revised New General Catalogue and Index Catalogue (RNGC/IC) (2024/2026 edition): Steinicke, W. 2010, Observing and Cataloguing Nebulae and Star Clusters (Cambridge Univ. Press); Verga, M. OpenNGC (CC-BY-SA 4.0 / data tables) — Wolfgang Steinicke / OpenNGC
- SH0ES Local Distance Ladder Hubble Constant (2022 Baseline Cepheid + SN Ia): Riess, A. G., et al. 2022, ApJL, 934, L7 (A Comprehensive Measurement of the Local Value of the Hubble Constant) — SH0ES Collaboration (HST / JWST)
- SIMBAD Astronomical Database (CDS) (2026-10 release): Wenger, M., et al. 2000, A&AS, 143, 9 (The SIMBAD astronomical database) — Centre de Données astronomiques de Strasbourg