Galaxies · Constellation Hydra

Southern Pinwheel Galaxy (Messier 83 / NGC 5236)

J2000 coordinates, Cepheid/TRGB distance (15.2 Mly), magnitude 7.54, barred spiral starburst core, six supernovae, and observing guide for Messier 83.

Right Ascension (J2000.0)13h 37m 00.91s
Declination (J2000.0)-29° 51′ 56.7″
Primary ClassificationFace-on grand-design barred spiral starburst galaxy (M83/Centaurus A Group)
Best Observing SeasonSpring to Early Summer (April–July)

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.

Astrometric, Photometric, and Physical Parameters for Southern Pinwheel Galaxy (Messier 83 / NGC 5236)
ParameterValueUncertaintyMethod & EpochQuality StatusSource Archive
Integrated visual magnitude (V)7.54 mag± 0.06 magWide-field integrated CCD photometrydefinitiveRevised New General Catalogue and Index Catalogue (RNGC/IC)
Distance in light-years15200000 ly± 500000 lyVLT Cepheids + HST Tip of the Red Giant Branch (4.66 ± 0.15 Mpc)definitiveSH0ES Local Distance Ladder Hubble Constant
Apparent major axis12.9 arcmin± 0.5 arcminOptical isophotal dimensions (12.9′ × 11.5′)definitiveRevised New General Catalogue and Index Catalogue (RNGC/IC)
Heliocentric recession velocity513 km/s± 2 km/sH I 21-cm synthesis velocity fielddefinitiveSIMBAD Astronomical Database (CDS)
Measurement Uncertainties & Competing Solutions: Classical Cepheid period-luminosity relations and HST ACS Tip of the Red Giant Branch (TRGB) star counts determine M83's distance to 4.66 ± 0.15 Mpc (15.2 ± 0.5 Mly).

J2000 Equatorial Sky Chart & Culmination Altitude

The chart below plots Southern Pinwheel (Messier 83 / NGC 5236) at RA 13h 37m 00.91s, Dec -29° 51′ 56.7″ within Hydra, 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.

J2000 Equatorial Sky Position (Hydra) +90° 0° −90° 24h 12h RA 0h Peak Meridian Altitude 20° 40°N Lat 90° 30°S Lat RA: 13h 37m 00.91s Dec: -29° 51′ 56.7″ Epoch: J2000.0 · V = 7.54 mag First-party vector diagram derived from IAU / CDS SIMBAD / Gaia DR3 astrometry.

Astrophysical Context & Structure

Nicolas-Louis de Lacaille discovered Messier 83 (NGC 5236), the Southern Pinwheel Galaxy, on February 23, 1752, from the Cape of Good Hope, making it the first galaxy outside the Local Group ever identified by humanity. Added to Messier's catalog in March 1781, M83 lies just 15.2 million light-years away on the southern Hydra–Centaurus border, where it anchors the northern sub-group of the nearby Centaurus A / M83 galaxy complex.

Measuring ~55,000 light-years across and viewed almost face-on, M83 is one of the brightest and closest barred spiral galaxies in the sky (V = 7.54). Hubble Wide Field Camera 3 and Chandra X-ray panoramas of M83 resolve thousands of young stellar clusters, crimson H-alpha emission nebulae, and nearly 300 supernova remnants threading its dusty spiral arms, along with a double nuclear structure driven by gas inflows along its prominent central stellar bar.

Over the past century M83 has produced six observed supernovae—SN 1923A, 1945B, 1950B, 1957D, 1968L, and 1983N (the prototype of stripped-envelope Type Ib core-collapse supernovae)—placing it among the top supernova-producing galaxies known.

Practical Visual Observing Guide

Minimum Instrument7×50 or 10×50 binoculars (200 mm+ telescope for bar and spiral arms)
Recommended Magnification60×–140×
Best Evening SeasonSpring to Early Summer (April–July)
  • Located 18° south of Spica on the Hydra–Centaurus border; at declination −29° 52′, it climbs only ~20°–30° above the southern horizon from mid-northern latitudes but passes near the zenith from the Southern Hemisphere.
  • Easily visible in 7×50 or 10×50 binoculars as a round 10′ glow with a bright center.
  • In a 200–300 mm telescope at 80×–140× under steady dark skies, M83 is one of the very few galaxies where visual observers can clearly trace a bright northeast-southwest central bar transitioning directly into two sweeping S-shaped spiral arms.

Catalog Cross-Identifications & Aliases

Common Aliases: M83 · NGC 5236 · UGCA 366 · Southern Pinwheel Galaxy

Cross-Catalog Identifiers for Southern Pinwheel Galaxy (Messier 83 / NGC 5236)
Catalog AuthorityIdentifier
MESSIERM 83
NGCNGC 5236
SIMBADM 83
WIKIDATAQ14030
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J2000 coordinates, TRGB/Cepheid distance (12.4 Mly), magnitude 6.84, warped dust lane, relativistic radio lobes, and observing guide for Centaurus A.

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J2000 coordinates, Cepheid/TRGB distance (21.6 Mly), magnitude 7.86, giant H II regions, SN 2011fe & SN 2023ixf, and observing guide for M101.

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Whirlpool Galaxy (Messier 51 / NGC 5194)

Coordinates, SN II-P / TRGB distance (8.58 Mpc / 28.0 Mly), grand-design spiral arms, NGC 5195 tidal companion, and observing guide for M51.

Reference Guide

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