Lacerta (abbr. Lac, gen. Lacertae) The Lizard. Lacerta is a small northern constellation that lies on the edge of the Milky Way just south of the midpoint of a line drawn from Deneb in Cygnus to Schedir in Cassiopeia. Its brightest star is Alpha Lac (visual magnitude 3.76, absolute magnitude 1.27, spectral type A1V, distance 102 light-years). Its most famous object is BL Lac, the prototype BL Lacertae object.