NGC 6752 (Caldwell 93 / Pavo Globular Cluster)
Coordinates, Gaia DR3 distance (4.12 kpc), magnitude 5.40, Bedin 1 background dwarf galaxy, and observing guide for NGC 6752 in Pavo.
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) | 5.4 mag | ± 0.05 mag | Wide-aperture integrated photometry | definitive | Catalog of Parameters for Milky Way Globular Clusters |
| Heliocentric distance | 13440 ly | ± 130 ly | Gaia DR3 trigonometric parallax + white-dwarf cooling (4.12 ± 0.04 kpc) (J2016.0) | definitive | ESA Gaia Archive — Data Release 3 |
| Apparent tidal diameter | 29 arcmin | ± 2 arcmin | Deep radial surface-density profile | high-confidence | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| White-dwarf cooling & turnoff age | 12.5 Gyr | ± 0.4 Gyr | HST ACS white-dwarf cooling sequence + main-sequence turnoff | high-confidence | Catalog of Parameters for Milky Way Globular Clusters |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots NGC 6752 (Great Peacock Globular Cluster) at RA 19h 10m 52.14s, Dec -59° 59′ 04.4″ within Pavo, 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
NGC 6752 (Caldwell 93, the Great Peacock Globular) is the fourth brightest globular cluster in the entire sky—surpassed only by Omega Centauri, 47 Tucanae, and M22—and one of the closest, orbiting just 13,440 light-years (4.12 ± 0.04 kiloparsecs) from Earth in the southern constellation Pavo. First cataloged by Scottish astronomer James Dunlop from Parramatta, Australia, on June 30, 1826, the cluster spans 29 arcminutes on the sky (nearly the size of the full Moon) and binds ~240,000 solar masses of stars.
Although classified optically as Shapley-Sawyer Class VI, high-resolution Hubble Space Telescope profiles show that NGC 6752's inner core has undergone gravothermal collapse and is currently sustained against deeper contraction by energy released from compact binary stars. It hosts nine known radio millisecond pulsars—two of which have been flung far out into the cluster halo with anomalously high spin-down accelerations, hinting at violent three-body encounters with a central black-hole binary or heavy remnant subsystem.
In 2019, while using HST to measure the faintest cooling white dwarfs in NGC 6752, astronomers serendipitously discovered 'Bedin 1' shining right through the cluster's foreground stars—an isolated, ancient dwarf spheroidal galaxy lying 30 million light-years in the background.
Practical Visual Observing Guide
- At declination −60°00′, NGC 6752 is a southern-hemisphere showpiece (invisible north of +25°N), located 3.5° east-northeast of Omega Pavonis.
- Shining at visual magnitude 5.40, it is easily visible to the naked eye under dark skies and resolves at the edges in 10×50 binoculars, with a foreground 7.3-magnitude blue star (HD 177999) clinging to its southwestern border.
- In any 80–150 mm telescope at 80×–150×, curving arms of 11th-to-13th magnitude orange and blue stars radiate outward like a cosmic windmill from a compact central cusp.
Catalog Cross-Identifications & Aliases
Common Aliases: NGC 6752 · Caldwell 93 · Great Peacock Globular · Windmill Globular
| Catalog Authority | Identifier |
|---|---|
| NGC | NGC 6752 |
| SIMBAD | NGC 6752 |
| WIKIDATA | Q502059 |
Related Objects, Comparisons & Guides
47 Tucanae (NGC 104 Globular Cluster)
Coordinates, Gaia distance (4.52 kpc), magnitude 4.09, millisecond pulsar core, and observing guide for 47 Tucanae (NGC 104).
Omega Centauri (NGC 5139 Cluster)
Coordinates, Gaia DR3 distance (5.43 kpc), magnitude 3.68, and multi-population core data for Omega Centauri (NGC 5139) in Centaurus.
Messier 22 (NGC 6656 Sagittarius Cluster)
Coordinates, Gaia DR3 distance (3.30 kpc), magnitude 5.10, stellar-mass black holes, and observing guide for Messier 22 in Sagittarius.
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.
Trigonometric Parallax, Parsecs & Gaia DR3
How trigonometric parallax (d_pc = 1 / p_arcsec), the distance modulus equation, Hipparcos, and Gaia DR3 microarcsecond astrometry measure cosmic distances.
Scientific Sources & Dataset Provenance
- Catalog of Parameters for Milky Way Globular Clusters (2010 / 2021 Gaia EDR3 revision): Harris, W. E. 1996 (2010 ed.), AJ, 112, 1487; Vasiliev, E. & Baumgardt, H. 2021, MNRAS, 505, 5978 — McMaster University / Gaia EDR3 Cluster Survey
- ESA Gaia Archive — Data Release 3 (DR3 (2022-06-13)): Gaia Collaboration, Vallenari, A., et al. 2023, A&A, 674, A1 (Gaia Data Release 3) — European Space Agency / Gaia DPAC
- 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