Messier 14 (NGC 6402)
Coordinates, Gaia DR3 distance (9.14 kpc), magnitude 7.59, Nova Ophiuchi 1938 history, and observing guide for Messier 14 in Ophiuchus.
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) | 7.59 mag | ± 0.06 mag | Integrated photoelectric & CCD photometry | definitive | Catalog of Parameters for Milky Way Globular Clusters |
| Heliocentric distance | 29800 ly | ± 650 ly | Gaia EDR3 + RR Lyrae & dynamical distance (9.14 ± 0.20 kpc) (J2016.0) | high-confidence | ESA Gaia Archive — Data Release 3 |
| Apparent diameter | 11 arcmin | ± 1 arcmin | Outer surface-brightness isophotes | high-confidence | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Main-sequence turnoff age | 12.3 Gyr | ± 0.6 Gyr | Reddening-corrected HST & ground-based CMD fitting | model-dependent | Catalog of Parameters for Milky Way Globular Clusters |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Messier 14 (NGC 6402 Globular Cluster) at RA 17h 37m 36.15s, Dec -03° 14′ 45.3″ within Ophiuchus, 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
Messier 14 (NGC 6402) is a massive, intrinsically luminous globular cluster in eastern Ophiuchus whose true brilliance is heavily veiled by interstellar dust clouds along the Milky Way plane. Discovered by Charles Messier on June 1, 1764, and located 29,800 light-years (9.14 ± 0.20 kiloparsecs) from Earth, M14 radiates about 400,000 times the luminosity of the Sun and contains roughly 750,000 solar masses of stars—making it physically more massive and luminous than M13 in Hercules, even though 1.9 magnitudes of visual dust extinction dim its apparent brightness to magnitude 7.59.
In June 1938, a classic thermonuclear nova erupted inside M14 when a white dwarf accreted hydrogen from a close companion, though the outburst was not discovered until Canadian astronomer Helen Sawyer Hogg inspected archival David Dunlap Observatory photographic plates in 1964. Peaking near photographic magnitude 16 (and likely reaching ~9.2 visual magnitude at true maximum), Nova Ophiuchi 1938 was the first nova ever photographed inside a globular cluster after T Scorpii in M80.
Photometric surveys have cataloged over 110 variable stars inside M14, including more than 90 RR Lyrae stars and five luminous Type II Cepheids, while MeerKAT radio timing observations recently uncovered five millisecond pulsars—including a 'black widow' eclipsing binary system—in its broad Class VIII core.
Practical Visual Observing Guide
- Situated in a relatively blank eastern zone of Ophiuchus, about 8.5° south of Cebalrai (β Ophiuchi) and 10° east-northeast of M10.
- Because dust extinction dims its brightest red giants to magnitude 14.0, M14 appears as a smooth, slightly oval 4–5 arcminute glow without resolved stars in binoculars and 100–150 mm telescopes.
- Apertures of 250–300 mm and larger at 160×–240× under dark skies begin to mottle the uniform disk into faint, dusty-looking starlight.
Catalog Cross-Identifications & Aliases
Common Aliases: M14 · NGC 6402
| Catalog Authority | Identifier |
|---|---|
| MESSIER | M 14 |
| NGC | NGC 6402 |
| SIMBAD | M 14 |
| WIKIDATA | Q11321 |
Related Objects, Comparisons & Guides
Messier 10 (NGC 6254 Globular Cluster)
Coordinates, Gaia DR3 distance (5.07 kpc), magnitude 6.4, blue-straggler core data, and observing guide for Messier 10 (NGC 6254) in Ophiuchus.
Messier 12 (NGC 6218 Gumball Globular)
Coordinates, Gaia DR3 distance (5.11 kpc), magnitude 6.70, tidal mass-loss history, and observing guide for Messier 12 (NGC 6218) in Ophiuchus.
Messier 80 (NGC 6093 Dense Scorpius Globular)
Coordinates, Gaia DR3 distance (10.34 kpc), magnitude 7.33, Nova T Scorpii 1860, blue-straggler core, and observing guide for M80 in Scorpius.
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.
Bortle Dark-Sky Scale & Sky Brightness Guide
Reference guide to the 9-class Bortle Dark-Sky Scale, zenith Sky Quality Meter (SQM) readings in mag/arcsec², naked-eye limiting magnitude, and light pollution.
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