well-known binary star, discovered in 1779 by William Herschel. The yellow, golden star (3.7mag) has a separation of 13" (with the separation changing from 5" to 16" over the period) and is accompanied by a companion of brightness 7.4mag with a red, purplish tint, which orbits it every 526 years. The binary star can be resolved in a 6 cm telescope.