Crater (The Cup) Constellation Sky Guide
Crater IAU constellation (282 sq deg, rank 53): April spring goblet perched on Hydra west of Corvus, led by +3.56 Delta Crateris and spiral galaxies.
Sky Navigation & Astrophysical Context
Resting on the midsection of Hydra immediately west of Corvus and south of Leo, Crater covers 282 square degrees of the spring sky (ranking 53rd in area). In Greco-Roman mythology and Ptolemy's Almagest, Crater, Corvus, and Hydra form a single narrative triad: Apollo sent the crow Corvus to fetch water in the golden goblet Crater, and the tardy bird blamed the water snake Hydra for blocking the spring.
Under dark rural skies, the constellation traces a recognizable tilted chalice of fourth-magnitude stars: the base is anchored by Alkes (Alpha Crateris, a K1 III metal-rich giant at +4.07) and Beta Crateris (+4.46), while the rim of the bowl is outlined by Gamma (+4.06), Zeta (+4.72), Eta (+5.17), Theta (+4.70), and the constellation's brightest member, the K0 III orange giant Delta Crateris (+3.56).
Looking away from the Milky Way plane toward the southern extension of the Virgo Supercluster, Crater hosts a series of interacting and barred spiral galaxies—including NGC 3511, NGC 3513, NGC 3887, and the colliding polar-ring system NGC 3981—as well as the Crater 2 Dwarf, an ultra-diffuse Local Group satellite galaxy with a half-light diameter of over 2 kiloparsecs discovered in 2016.
Equatorial Center Position & Transit Altitude
Crater is centered near Right Ascension 11h 23m 24s, Declination −15° 55′ 48″ (The Cup (Goblet)).
Practical Star-Hopping & Observing Tips
- Locate the bright quadrilateral of Corvus first, then shift 10° west along Hydra's back to trace the 7°-wide semicircle of the Crater goblet.
- Split Gamma Crateris (+4.06) in a 100 mm telescope at 120× to reveal its +9.6-magnitude companion separated by 5.2 arcseconds.
- Sweep 2° west of Beta Crateris with a 150 mm+ telescope to view the paired spiral galaxies NGC 3511 (+11.0) and NGC 3513 (+11.5) in the same low-power field.
Notable Celestial Objects in & Near Crater
| Object | Family | Classification | RA (J2000) | Dec (J2000) | Min. Instrument |
|---|---|---|---|---|---|
| Sombrero Galaxy (Messier 104 / NGC 4594) | galaxies | Unbarred early-type spiral / lenticular-halo galaxy with edge-on dust ring | 12h 39m 59.43s | -11° 37′ 23.0″ | 60–80 mm telescope (150 mm+ to clearly trace the dark equatorial dust lane) |
| Spica (Alpha Virginis Ellipsoidal Binary) | stars | Double-lined spectroscopic & rotating ellipsoidal B-type binary (Beta Cephei variable) | 13h 25m 11.58s | -11° 09′ 40.8″ | Naked eye |
Scientific Sources Cited
- IAU Official Constellation Boundaries & Designations (IAU 88 Recognized Constellations): Delporte, E. 1930, Délimitation scientifique des constellations (IAU / Cambridge University Press) — International Astronomical Union (IAU)
- 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