Open Clusters · Constellation Perseus

Messier 34 (NGC 1039)

Coordinates, Gaia DR3 distance (507 pc), magnitude 5.2, central visual binary Otto Struve 44, and observing guide for M34 in Perseus.

Right Ascension (J2000.0)02h 42m 06.00s
Declination (J2000.0)+42° 45′ 42.0″
Primary ClassificationOpen star cluster
Best Observing SeasonAutumn to Winter (September–February)

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 Messier 34 (NGC 1039)
ParameterValueUncertaintyMethod & EpochQuality StatusSource Archive
Integrated visual magnitude (V)5.2 mag± 0.1 magWide-aperture integrated photometrydefinitiveRevised New General Catalogue and Index Catalogue (RNGC/IC)
Heliocentric distance1650 ly± 20 lyGaia DR3 astrometric parallax of ~500 member stars (507 ± 6 pc) (J2016.0)definitiveESA Gaia Archive — Data Release 3
Apparent diameter35 arcmin± 3 arcminVisual and Gaia DR3 member core extenthigh-confidenceRevised New General Catalogue and Index Catalogue (RNGC/IC)
Gyrochronology & lithium turnoff age0.22 Gyr± 0.025 GyrGaia DR3 isochrone + TESS/WIYN solar-type rotation periodshigh-confidenceESA Gaia Archive — Data Release 3
Measurement Uncertainties & Competing Solutions: Gaia DR3 fixes M34's distance at 507 ± 6 pc (1,650 light-years), while combining main-sequence turnoff isochrones with TESS stellar rotation periods (gyrochronology) narrows its age to 220 ± 25 Myr.

J2000 Equatorial Sky Chart & Culmination Altitude

The chart below plots Messier 34 (NGC 1039 Spiral Cluster) at RA 02h 42m 06.00s, Dec +42° 45′ 42.0″ within Perseus, 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 (Perseus) +90° 0° −90° 24h 12h RA 0h Peak Meridian Altitude 87° 40°N Lat 17° 30°S Lat RA: 02h 42m 06.00s Dec: +42° 45′ 42.0″ Epoch: J2000.0 · V = 5.2 mag First-party vector diagram derived from IAU / CDS SIMBAD / Gaia DR3 astrometry.

Astrophysical Context & Structure

Messier 34 (NGC 1039) is a bright, coarse open cluster located 1,650 light-years (507 ± 6 parsecs) away in western Perseus, near the border with Andromeda. First noted by Giovanni Battista Hodierna before 1654 and independently cataloged by Charles Messier on August 25, 1764, M34 spans 35 arcminutes across the sky—slightly larger than the full Moon—corresponding to a true physical diameter of roughly 17 light-years.

At an age of ~220 million years and a slightly supersolar metallicity ([Fe/H] ≈ +0.07 dex), M34 serves as a critical evolutionary stepping stone between the 115-million-year-old Pleiades (M45) and the 650-million-year-old Hyades. Photometric monitoring of its ~500 confirmed G-, K-, and M-dwarf members has mapped how young solar-type stars shed angular momentum via magnetized stellar winds as they transition from rapid convecting rotators to slow, stable spinners.

Visually, M34 is famous for its gracefully curving 'spiral' or C-shaped arcs of 8th- and 9th-magnitude B8–A0 stars and for the striking equal-brightness pair of double stars near its geometric center (h 1123 with a 20″ separation and Otto Struve 44 / ΟΣ 44 with a tight 1.4″ separation).

Practical Visual Observing Guide

Minimum InstrumentNaked eye / 7×50 binoculars
Recommended Magnification20×–50× wide-field
Best Evening SeasonAutumn to Winter (September–February)
  • Easy to locate midway along the line connecting Algol (β Persei) to Almach (γ Andromedae), about 5° northwest of Algol.
  • Visible to the naked eye at magnitude 5.2 from dark sites, and resolves cleanly into a dozen stars in 7×50 or 10×50 binoculars.
  • Use a wide-field telescope at 25×–45× to enjoy the curving stellar arcs and split the 8th-magnitude twin pair h 1123 (20″ separation) at the center; increase power to 150×+ in a 100 mm+ aperture to split the 1.4″ binary ΟΣ 44 just northwest.

Catalog Cross-Identifications & Aliases

Common Aliases: M34 · NGC 1039 · Spiral Cluster

Cross-Catalog Identifiers for Messier 34 (NGC 1039)
Catalog AuthorityIdentifier
MESSIERM 34
NGCNGC 1039
SIMBADM 34
WIKIDATAQ11386
Related Object · Perseus

Double Cluster (NGC 869 & NGC 884)

Coordinates, Gaia DR3 distance (2.29 kpc), age 14 Myr, supergiant population, and observing guide for NGC 869 and NGC 884 in Perseus.

Related Object · Taurus

Pleiades (Messier 45 Open Cluster)

Coordinates, Gaia DR3 distance (136.2 pc), magnitude 1.6, reflection nebulosity, and observing guide for the Pleiades (M45) in Taurus.

Reference Guide

Angular Size, Separation & Field of View

How angular diameter (degrees, arcminutes, arcseconds), spherical angular separation, and small-angle physical diameter relate to telescope field of view.

Reference Guide

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

  • 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
  • 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
  • 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