Open Cluster NGC 2420

NGC 2420
NGC 2420: Open cluster in Gemini; 500 mm Cassegrain f=3625mm / f7.2; SBIG STL11K; 180+3*40 min LRGB; Bernese Highlands; © 2015 Radek Chromik

Object Description

NGC 2420 was discovered on 19 November 1783 by the German-British astronomer Wilhelm Herschel with its 18.7 inch reflector. It is a Trumpler-type I2r open star cluster of about magnitude 8.3 visual magnitude. [277]

The open star cluster NGC 2420 (also known as Collinder 154, Melotte 69) has an estimated age of 2.5 ± 0.5 billion years. The parallax of the cluster determined from Gaia DR2 2018 gives a distance of 2.55 ± 0.5 kpc (about 8300 light years). There is little interstellar dust on the line of sight, resulting in little blushing of the starlight. [384] The cluster counts 685 ± 27 member stars within a radius of 20 arc minutes, which corresponds to about 12 pc (39 light years). The radius of the core is about 1.32 arc minutes. [385]

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
DesignationNGC 2420
TypeOCL (I2r)
Right Ascension (J2000.0)07h 38m 23.8s
Declination (J2000.0)+21° 34' 27"
Diameter6 arcmin
Visual magnitude8.3 mag
Metric Distance2.500 kpc
Dreyer DescriptionCl, cL, Ri, C, st 11…18
Identification, RemarksOCL 488

Finder Chart

Open star cluster NGC 2420 is located in the constellation of Gemini, some 2° 15' east of the Eskimo Nebula (NGC 2392). The best viewing time is October to April.

Finder Chart Open Cluster NGC 2420
Open Cluster NGC 2420 in constellation Gemini. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

More Objects Nearby (±15°)


  • [149] SkySafari 6 Pro, Simulation Curriculum;
  • [160] The STScI Digitized Sky Survey;
  • [277] «Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; (2021-02-17)
  • [384] «The Gaia-ESO survey: 3D NLTE abundances in the open cluster NGC 2420 suggest atomic diffusion and turbulent mixing are at the origin of chemical abundance variations» Ekaterina Semenova, Maria Bergemann, Morgan Dea, Aldo Serenelli, Camilla Juul Hansen, Andrew J. Gallagher, Amelia Bayo, Thomas Bensby, Angela Bragaglia, Giovanni Carraro, Lorenzo Morbidelli, Elena Pancino and Rodolfo Smiljanic; A&A Volume 643, November 2020; DOI:10.1051/0004-6361/202038833
  • [385] «Star Counts in the Open Cluster NGC 2420» Leonard, Peter J. T.; Astronomical Journal v.95, p.108, January 1988; DOI:10.1086/114617