Messier 35 (NGC 2168)
Coordinates, Gaia DR3 distance (889 pc), magnitude 5.1, background cluster NGC 2158 contrast, and observing guide for M35 in Gemini.
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) | 5.1 mag | ± 0.1 mag | Wide-aperture integrated photometry | definitive | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Heliocentric distance | 2900 ly | ± 50 ly | Gaia DR3 astrometric parallax of ~1,300 members (889 ± 15 pc) (J2016.0) | definitive | ESA Gaia Archive — Data Release 3 |
| Apparent diameter | 28 arcmin | ± 2 arcmin | Visual and Gaia DR3 member core extent | high-confidence | Revised New General Catalogue and Index Catalogue (RNGC/IC) |
| Main-sequence turnoff & white-dwarf age | 0.15 Gyr | ± 0.02 Gyr | Gaia DR3 isochrone + massive white-dwarf cooling calibration | high-confidence | ESA Gaia Archive — Data Release 3 |
J2000 Equatorial Sky Chart & Culmination Altitude
The chart below plots Messier 35 (NGC 2168 & NGC 2158 Pair) at RA 06h 08m 54.00s, Dec +24° 20′ 00.0″ within Gemini, 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 35 (NGC 2168, the Shoe-Buckle Cluster) is one of the grandest open clusters of the northern winter sky, situated 2,900 light-years (889 ± 15 parsecs) away near the Castor foot of Gemini. Discovered by Jean-Philippe Loys de Chéseaux in 1745 and independently by English astronomer John Bevis before 1750, M35 spans 28 arcminutes across the sky—matching the apparent diameter of the full Moon—and measures roughly 24 light-years in physical width.
Containing more than 1,300 confirmed stars and a total dynamical mass of ~1,600 to 2,500 solar masses, M35 is about 150 million years old—just slightly older than the Pleiades. Because its initial population included stars up to 5–8 solar masses that have already completed their lifetimes, M35 contains over a dozen massive, hot carbon-oxygen and oxygen-neon white dwarfs used to calibrate the upper mass limit for white-dwarf formation versus core-collapse supernovae.
What makes M35 a legendary visual showpiece is the dramatic perspective effect just 25 arcminutes southwest of its center: tucked against M35's bright outer rim sits NGC 2158, an ancient (~2-billion-year-old), richly compressed open cluster lying 13,000 light-years away in the outer Perseus Arm—more than four times the distance of M35.
Practical Visual Observing Guide
- Located 2.3° northwest of Eta Geminorum (Propus) and Mu Geminorum (Tejat) at the western foot of Gemini.
- Visible to the naked eye at magnitude 5.1 under dark skies; 10×50 binoculars resolve dozens of 8th-to-10th magnitude stars arranged in looping chains around a slightly star-poor central void.
- In a 100–200 mm telescope with a wide-field eyepiece at 40×–80×, both M35 and the frosty, globular-like 8.6-magnitude patch of NGC 2158 fit in the same field of view; boost power to 140×+ on NGC 2158 to resolve its 14th-magnitude stars.
Catalog Cross-Identifications & Aliases
Common Aliases: M35 · NGC 2168 · Shoe-Buckle Cluster
| Catalog Authority | Identifier |
|---|---|
| MESSIER | M 35 |
| NGC | NGC 2168 |
| SIMBAD | M 35 |
| WIKIDATA | Q11388 |
Related Objects, Comparisons & Guides
Messier 37 (NGC 2099 Salt-and-Pepper Cluster)
Coordinates, Gaia DR3 distance (1.42 kpc), magnitude 5.6, central red giant HD 250068, and observing guide for Messier 37 in Auriga.
Pinwheel Cluster (Messier 36 / NGC 1960)
Coordinates, Gaia DR3 distance (1.17 kpc), magnitude 6.0, young B-star kinematics, and observing guide for Messier 36 in Auriga.
Starfish Cluster (Messier 38 / NGC 1912)
Coordinates, Gaia DR3 distance (1.13 kpc), magnitude 6.4, binary cluster pair NGC 1907, and observing guide for Messier 38 in Auriga.
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.
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.
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