Epsilon and Zeta Crateris mark the Cup's rim. The largest naked eye star in the constellation, Epsilon Crateris is an evolved K-type giant star with a stellar classification of K5 III. It has about the same mass as the Sun, but has expanded to 44.7 times the Sun's radius. The star is radiating 391 times the solar luminosity. It is 366 ± 8 light-years distant from the Sun. Zeta Crateris is a binary star system. The primary, component A, is a magnitude 4.95 evolved giant star with a stellar classification of G8 III. It is a red clump star that is generating energy through the fusion of helium at its core. Zeta Crateris has expanded to 13 times the radius of the Sun, and shines with 157 times the luminosity of the Sun. The secondary, component B, is a magnitude 7.84 star. Zeta Crateris is a confirmed member of the Sirius supercluster and is a candidate member of the Ursa Major Moving Group, a collection of stars that share a similar motion through space and may have at one time been members of the same open cluster. The system is located 326 ± 9 light-years from the Sun.