Antennae Galaxies (NGC 4038 / NGC 4039 / Arp 244 / Caldwell 60–61)
J2000 coordinates, TRGB distance (65.2 Mly), magnitude 10.32, colliding spiral pair, 500,000-ly tidal tails, and observing guide for the Antennae.
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 |
|---|---|---|---|---|---|
| Combined visual magnitude (V) | 10.32 mag | ± 0.1 mag | Integrated CCD aperture photometry of NGC 4038 + NGC 4039 cores | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Distance in light-years | 65200000 ly | ± 3900000 ly | Revised HST Tip of the Red Giant Branch + SN 2007sr Type Ia (20.0 ± 1.2 Mpc) | definitive | SH0ES Local Distance Ladder Hubble Constant |
| Apparent major axis (cores; tails span 20′) | 5.2 arcmin | ± 0.4 arcmin | Optical 25 mag/arcsec² isophotal dimensions of colliding disks (5.2′ × 3.1′) | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric recession velocity | 1642 km/s | ± 6 km/s | ALMA CO & H I 21-cm systemic velocity | definitive | SIMBAD Astronomical Database (CDS) |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Antennae Galaxies (NGC 4038 & NGC 4039) at RA 12h 01m 53.00s, Dec -18° 52′ 03.3″ within Corvus, 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 William Herschel on February 7, 1785, in western Corvus, the Antennae Galaxies (NGC 4038 and NGC 4039, cataloged together as Arp 244 and Caldwell 60/61) are the nearest and youngest example of a major collision between two large, gas-rich spiral galaxies at a distance of 65.2 million light-years. In their classic 1972 N-body computer simulation paper 'Galactic Bridges and Tails', brothers Alar and Juri Toomre modeled NGC 4038/4039 to prove that the pair's two 500,000-light-year-long curving streams of stars and gas—which resemble the antennae of an insect—were flung outward by gravitational tidal forces during their first pericenter passage ~600 million years ago.
Now locked in the violent second phase of their merger, the two galactic disks are overlapping and colliding head-on. Where billions of solar masses of cold molecular gas clouds crash together in the overlap zone between the two nuclei, Hubble Space Telescope, ALMA, and JWST images resolve more than 1,000 newborn 'super-star clusters'—each packing up to a million young massive stars into a volume the size of a globular cluster, serving as modern-day progenitors of globular clusters.
Within roughly 400 million years the two spiral nuclei of NGC 4038 and NGC 4039 will coalesce completely into a single giant elliptical galaxy, offering a preview of the future collision between our Milky Way and the Andromeda Galaxy 4.5 billion years from now. Five supernovae have been recorded in the Antennae: SN 1921A, 1974E, 2004gt, 2007sr, and 2013dk.
Practical Visual Observing Guide
- Located 3.5° southwest of Gienah (γ Corvi, the top-right star of the sail of Corvus).
- In a 100–150 mm telescope at 80×–120×, the pair appears as a peanut- or comma-shaped glow where the brighter northern disk (NGC 4038) meets the southern extension (NGC 4039).
- In a 250–400 mm (10–16 inch) telescope at 140×–200× under dark skies, you can resolve the two intersecting, heart-shaped rings of star-forming knots—while ultra-dark Bortle 1–2 skies with a 400 mm+ aperture can trace the base of the southern tidal tail.
Catalog Cross-Identifications & Aliases
Common Aliases: Antennae Galaxies · NGC 4038 · NGC 4039 · Arp 244 · Caldwell 60 · Ringtail Galaxy
| Catalog Authority | Identifier |
|---|---|
| NGC | NGC 4038 |
| SIMBAD | NGC 4038 |
| WIKIDATA | Q487236 |
Related Objects, Comparisons & Guides
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.
Centaurus A (NGC 5128 Active Radio Galaxy)
J2000 coordinates, TRGB/Cepheid distance (12.4 Mly), magnitude 6.84, warped dust lane, relativistic radio lobes, and observing guide for Centaurus A.
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.
Measurement Uncertainty & Optics in Astronomy
How random vs systematic errors, asymmetric error bars, model dependencies, and optical aperture/exit-pupil limits shape astronomical measurements.
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