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.
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) | 8.24 mag | ± 0.06 mag | Integrated CCD aperture photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Distance in light-years | 15000000 ly | ± 500000 ly | HST Tip of the Red Giant Branch (TRGB: 4.61 ± 0.15 Mpc) | definitive | SH0ES Local Distance Ladder Hubble Constant |
| Apparent major axis | 11.2 arcmin | ± 0.5 arcmin | Optical isophotal dimensions including outer ring (11.2′ × 9.1′) | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric recession velocity | 308 km/s | ± 1 km/s | THINGS H I 21-cm synthesis velocity field | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Cat's Eye Galaxy (Messier 94 / NGC 4736) at RA 12h 50m 53.06s, Dec +41° 07′ 13.6″ within Canes Venatici, 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
Discovered by Pierre Méchain on March 22, 1781, and cataloged by Charles Messier two days later, Messier 94 (NGC 4736, often called the Cat's Eye or Croc's Eye Galaxy) is the gravitational centerpiece of the nearby Canes Venatici I Cloud just 15.0 million light-years from Earth. Viewed nearly face-on, M94 is famous for its concentric double-ring architecture spanning roughly 50,000 light-years across its outer pseudoring.
Surrounding M94's intense LINER nucleus is a dazzling inner starburst ring roughly 70 arcseconds (~5,000 light-years) in diameter, where an oval distortion in the central stellar bulge acts like a cosmic paddle, driving an outward-propagating resonance wave that compresses gas into a continuous necklace of young blue star clusters and H II regions. Multi-wavelength ultraviolet (GALEX) and infrared (Spitzer) imaging further showed that the faint 11-arcminute outer ring is not a closed tidal loop, but a pair of tightly wound, star-forming spiral arms containing ~10% of the galaxy's young stellar mass.
In 2008 deep H I 21-centimeter rotation curves of M94 sparked intense astrophysical debate when researchers noted that its outer gas rotation speed drops off faster than in typical spiral galaxies, suggesting either a strongly warped outer gas disk or an unusually low-concentration dark-matter halo.
Practical Visual Observing Guide
- Forms the northern vertex of a flat isosceles triangle about 2.8° northwest of the line connecting Cor Caroli (α CVn) and Chara (β CVn).
- Because its inner 1′ starburst ring and core have one of the highest surface brightnesses of any Messier galaxy, M94 is easily visible in 7×50 binoculars and looks almost like a bright globular cluster in small refractors.
- In a 150–250 mm telescope at 120×–180×, the blazing central core is surrounded by a distinct, sharp-edged 2′ inner ring fading into a ghostly outer halo.
Catalog Cross-Identifications & Aliases
Common Aliases: M94 · NGC 4736 · UGC 7996 · Croc's Eye Galaxy
| Catalog Authority | Identifier |
|---|---|
| MESSIER | M 94 |
| NGC | NGC 4736 |
| SIMBAD | M 94 |
| WIKIDATA | Q14058 |
Related Objects, Comparisons & Guides
Sunflower Galaxy (Messier 63 / NGC 5055)
J2000 coordinates, TRGB distance (29.3 Mly), magnitude 8.59, flocculent spiral arms, warped H I disk, and observing guide for Messier 63 (NGC 5055).
Messier 106 (NGC 4258 Megamaser Anchor)
J2000 coordinates, geometric maser distance (24.7 Mly), magnitude 8.41, anomalous synchrotron arms, Seyfert 2 core, and observing guide for M106.
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.
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.
Apparent vs Absolute Magnitude Explained
Understand the logarithmic Pogson astronomical magnitude scale, apparent visual magnitude (m), absolute magnitude (M at 10 parsecs), and bolometric corrections.
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