Sculptor Galaxy (NGC 253 / Silver Coin / Caldwell 65)
J2000 coordinates, TRGB distance (11.4 Mly), magnitude 7.20, nuclear starburst superwind, mottled dust lanes, and observing guide for NGC 253.
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) | 7.2 mag | ± 0.06 mag | Wide-field integrated CCD aperture photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Distance in light-years | 11400000 ly | ± 400000 ly | HST ACS Tip of the Red Giant Branch (TRGB: 3.50 ± 0.12 Mpc) | definitive | SH0ES Local Distance Ladder Hubble Constant |
| Apparent major axis | 27.5 arcmin | ± 0.9 arcmin | Optical 25 mag/arcsec² isophotal dimensions (27.5′ × 6.8′) | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric recession velocity | 243 km/s | ± 2 km/s | H I 21-cm and ALMA CO molecular rotation curve | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Sculptor Galaxy (NGC 253 Silver Coin) at RA 00h 47m 33.13s, Dec -25° 17′ 19.7″ within Sculptor, 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
Caroline Herschel discovered the Sculptor Galaxy (NGC 253, universally known as the Silver Coin or Silver Dollar Galaxy) on September 23, 1783, while sweeping for comets from Slough, England, with a small 4.2-inch Newtonian reflector built for her by her brother William. Located just 11.4 million light-years away near the South Galactic Pole in Sculptor, NGC 253 is the brightest and most massive member of the Sculptor Filament—one of the nearest galaxy groups outside the Local Group—and ranks as the brightest spiral galaxy in the sky after Andromeda (M31), Triangulum (M33), and Bode's Galaxy (M81).
Tilted 78 degrees from face-on and stretching nearly half a degree (27.5 × 6.8 arcminutes, or ~90,000 light-years) across the sky, NGC 253 is rivaled only by M82 as the closest nuclear starburst galaxy to Earth. Inside its central 1,500 light-years, a near-infrared bar funnels giant molecular clouds (mapped by ALMA) into a furious starburst nursery that forms new stars at ~5 solar masses per year and hosts several young 'super-star clusters' each weighing up to 1.5 million solar masses.
Driven by thousands of OB-star winds and core-collapse supernovae in that compact core, a bipolar 'superwind' of X-ray-emitting plasma and molecular gas erupts perpendicular to NGC 253's disk at up to 600 km/s, while the galaxy is also detected in teraelectronvolt gamma rays by the Fermi and H.E.S.S. observatories.
Practical Visual Observing Guide
- Located 7.5° south-southwest of Diphda (β Ceti); sits only 1.8° northwest of the large, loose globular cluster NGC 288.
- Combining magnitude 7.20 with a high-surface-brightness edge-on tilt, NGC 253 is one of the most spectacular visual galaxies in the entire sky: even 10×50 binoculars reveal a glowing 25′-long silver cigar.
- In a 150–300 mm telescope at 70×–140×, NGC 253 fills the eyepiece from edge to edge with mottled dark dust knots, bright star clouds, and foreground field stars.
Catalog Cross-Identifications & Aliases
Common Aliases: NGC 253 · Silver Coin Galaxy · Silver Dollar Galaxy · Caldwell 65 · PGC 2789
| Catalog Authority | Identifier |
|---|---|
| NGC | NGC 253 |
| SIMBAD | NGC 253 |
| WIKIDATA | Q490105 |
Related Objects, Comparisons & Guides
Cigar Galaxy (Messier 82 Starburst Galaxy)
Coordinates, TRGB distance (3.53 Mpc / 11.5 Mly), starburst superwind, dark dust filaments, and observing guide for the Cigar Galaxy (M82).
Andromeda Galaxy (Messier 31 / NGC 224)
Coordinates, Cepheid/TRGB distance (765 kpc / 2.50 Mly), magnitude 3.44, blueshift (−300 km/s), and observing guide for Andromeda (M31).
Cartwheel Galaxy (ESO 350-40 Ring Galaxy)
J2000 coordinates, distance (489 Mly), magnitude 15.20, bullseye collisional ring, JWST dust spokes, ultraluminous X-ray sources, and observing guide.
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