IAU Constellation (Com) · Genitive: Comae Berenices · Northern Sky

Coma Berenices (Berenice's Hair) Guide

Coma Berenices IAU constellation (386 sq deg, rank 42): May North Galactic Pole region hosting the Coma Star Cluster (Mel 111) and Coma Galaxy Cluster.

Solid-Angle Area386 sq deg (Rank #42 of 88)
Best Evening MonthMay
Visibility Latitudes+90° to −70°
Brightest StarBeta Comae Berenices (+4.25)

Sky Navigation & Astrophysical Context

Covering 386 square degrees between Leo, Virgo, and Boötes, Coma Berenices is the only modern IAU constellation named after a historical person: Queen Berenice II of Ptolemaic Egypt, who sacrificed her long amber tresses to the temple of Aphrodite in 246 BCE for the safe return of her husband Ptolemy III Euergetes from the Third Syrian War, and whose court astronomer Conon of Samos identified the shimmering star cluster east of Leo's tail as her elevated locks.

That cascading V-shaped naked-eye star cloud is the Coma Star Cluster (Melotte 111 / Collinder 256), a 4.5°-wide open cluster of ~40 fourth- to seventh-magnitude A, F, and G stars lying at just 85.7 parsecs (280 light-years)—the third-closest open cluster to Earth after the Hyades and the Ursa Major Moving Group. Meanwhile, the constellation's brightest individual star is Beta Comae Berenices (+4.25), a nearby G0 V solar twin at 9.18 parsecs.

Coma Berenices contains the exact North Galactic Pole (RA 12h 51m 26s, Dec +27° 07′ 42″), giving observers zero foreground Milky Way dust extinction. Consequently, it encloses eight Messier objects (globular M53 and northern Virgo Cluster spirals M64 [the Black Eye Galaxy], M85, M88, M91, M98, M99, and M100), the edge-on Needle Galaxy (NGC 4565), and the Rich Coma Cluster of galaxies (Abell 1656) at ~100 megaparsecs, where Fritz Zwicky first inferred dark matter in 1933.

Bordering IAU Constellations: Canes Venatici, Ursa Major, Leo, Virgo, Boötes.

Equatorial Center Position & Transit Altitude

Coma Berenices is centered near Right Ascension 12h 47m 24s, Declination +23° 18′ 36″ (Berenice's Hair).

J2000 Equatorial Sky Position (Coma Berenices) +90° 0° −90° 24h 12h RA 0h Peak Meridian Altitude 73° 40°N Lat 37° 30°S Lat RA: 12h 47m 24s Dec: +23° 18′ 36″ Epoch: J2000.0 · 386 sq deg (Rank #42) First-party vector diagram derived from IAU / CDS SIMBAD / Gaia DR3 astrometry.

Practical Star-Hopping & Observing Tips

  • Scan the 5° V-shaped wedge of the Coma Star Cluster (Melotte 111) below Gamma Comae Berenices with 7×50 or 10×50 binoculars for one of the best wide-field views in the spring sky.
  • Point a 150 mm+ telescope 2° east of Gamma Comae to trace the razor-thin 16-arcminute profile and dark central dust lane of the Needle Galaxy (NGC 4565).
  • Hop 1° northeast of Alpha Comae Berenices (Diadem) to observe the globular cluster Messier 53, and 1° northeast of 35 Comae for the Black Eye Galaxy (M64).

Notable Celestial Objects in & Near Coma Berenices

Cataloged Stars and Deep-Sky Objects Associated with Coma Berenices
ObjectFamilyClassificationRA (J2000)Dec (J2000)Min. Instrument
Messier 87 (Virgo A Giant Elliptical Galaxy)galaxiesSupergiant cD elliptical galaxy & active galactic nucleus (Virgo Cluster center)12h 30m 49.42s+12° 23′ 28.0″60–80 mm telescope (10×50 binoculars under dark skies)
Whirlpool Galaxy (Messier 51 / NGC 5194)galaxiesInteracting grand-design spiral galaxy pair13h 29m 52.70s+47° 11′ 42.9″70–100 mm telescope (200 mm+ under dark skies to resolve spiral arms)
Messier 53 (NGC 5024 Outer Halo Globular)globular-clustersGlobular cluster13h 12m 55.25s+18° 10′ 05.4″10×50 binoculars
Black Eye Galaxy (Messier 64 / NGC 4826)galaxiesEarly-type spiral galaxy with dark nuclear dust hood and counter-rotating outer gas disk12h 56m 43.69s+21° 40′ 57.6″60–80 mm telescope (150 mm+ at 150×+ to see the dark 'Black Eye' dust lane)
Messier 85 (NGC 4382 Merger-Remnant S0)galaxiesPeculiar lenticular S0 galaxy with merger shells (northernmost Virgo Messier member)12h 25m 24.05s+18° 11′ 27.9″70–80 mm telescope (120 mm+ to clearly show companion NGC 4394)
Messier 88 (NGC 4501 Symmetrical Spiral)galaxiesMulti-arm symmetrical spiral & Seyfert 2 galaxy in the Virgo Cluster12h 31m 59.16s+14° 25′ 13.2″80–100 mm telescope
Coma Pinwheel Galaxy (Messier 99 / NGC 4254)galaxiesAsymmetric face-on grand-design SA(s)c spiral galaxy in the Virgo Cluster12h 18m 49.63s+14° 24′ 59.3″80–100 mm telescope (250 mm+ to resolve the asymmetric spiral arms)
Mirror Galaxy (Messier 100 / NGC 4321)galaxiesFace-on grand-design SAB(s)bc spiral galaxy (brightest Virgo Cluster spiral)12h 22m 54.90s+15° 49′ 20.3″80–100 mm telescope (250 mm+ for spiral arms)
Needle Galaxy (NGC 4565 Edge-On Spiral)galaxiesArchetypal edge-on giant spiral galaxy with boxy/peanut pseudobulge12h 36m 20.78s+25° 59′ 14.6″80–100 mm telescope (200 mm+ to trace the full dark dust lane)

Scientific Sources Cited