Double Cluster vs Pleiades (M45) Comparison
Compare the young Perseus OB1 Double Cluster (NGC 869/884, 14 Myr) against the nearer Pleiades (M45, 115 Myr) in supergiants, distance, and optics.
Compared Celestial Objects
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.
Constellation: Perseus · Coords: 02h 20m 00.00s, +57° 08′ 00.0″
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.
Constellation: Taurus · Coords: 03h 47m 00.00s, +24° 07′ 00.0″
Normalized Shared Parameter Table
| Parameter | Unit / Scale | Double Cluster (NGC 869 & NGC 884) | Pleiades (Messier 45 Open Cluster) |
|---|---|---|---|
| Integrated Visual Magnitude (V) | mag | +3.7 (NGC 869: +4.3, NGC 884: +4.4) | +1.60 ± 0.05 |
| Gaia DR3 Heliocentric Distance | pc | 2,250 ± 70 pc (7,340 ly) | 136.2 ± 1.2 pc (444 ly) |
| Apparent Angular Span | arcmin | 60 × 30′ (twin 30′ cores) | 110 ± 10′ (1.8°) |
| Isochrone Age | Myr | 13.5 ± 1.5 Myr | 115 ± 10 Myr |
| Combined Stellar Mass | M☉ | ~20,000 M☉ (with Per OB1 halo) | ~800 M☉ |
Astrophysical & Observational Synthesis
At first glance with the unaided eye, the Pleiades (M45) at V = +1.60 outshines the misty 4th-magnitude patch of the Double Cluster in Perseus. Yet the Double Cluster (NGC 869 and NGC 884) lies 16.5 times farther away in the Perseus spiral arm (2,250 pc vs 136.2 pc)—meaning its distance modulus is 6.09 magnitudes larger than M45's.
If the Double Cluster were brought to the 136-parsec distance of the Pleiades, its twin cores would blaze across 15 degrees of sky with dozens of stars brighter than first magnitude and outshine Venus in total integrated light. At just ~13.5 Myr old and ~20,000 M☉ total mass, NGC 869 and NGC 884 are true young super-clusters packed with luminous B0–B2 supergiants and evolved M-type red supergiants.
Because M45 is 16.5× closer and 25× less massive (~800 M☉), it requires ultra-wide binoculars or a rich-field finder (2°+ field) to frame its Seven Sisters, whereas the Double Cluster's two 30-arcminute cores fit side-by-side inside a 1-degree low-power telescope eyepiece (35×–60×).
Related Reference Guides
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.
Stellar Spectral Classification (OBAFGKM)
Reference guide to Morgan-Keenan (MK) stellar classification (O B A F G K M), luminosity classes (I–V, WD), color index (B-V), and the H-R diagram.
Primary Catalogs & Scientific Sources
- 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
- 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