Columba, constellation in the southern sky at about 6 hours right ascension and 35° south in declination. Its brightest star is Alpha Columbae (sometimes called Phact, from the Arabic for “ring dove”), with a magnitude of 2.6. In 1612 Dutch cartographer Petrus Plancius introduced this constellation on a celestial globe he made and represented it as the dove that the biblical figure Noah released from the ark.