Dim companion of sirius

Using a newly ground 18-inch lens, Clark saw an anomaly near Sirius. The existence of a dark companion star orbiting Sirius was confirmed through its gravitational influence. This discovery added to the understanding of binary star systems.
 Alvan Graham Clark United States 1862 Dim companion of sirius

Using a newly ground 18-inch lens, Clark saw an anomaly near Sirius. The existence of a dark companion star orbiting Sirius was confirmed through its gravitational influence. This discovery added to the understanding of binary star systems.