Welcome to the Visual Binaries.

After having discovered Uranus in 1781, Herschel turned to the study of stars, and tried to find the relative distances of stars from each other, and from our own Sun. Having noted, after years of observation, that many stars had close neighbours, and that these neighbouring stars were usually much dimmer, he reasoned that the brighter star was closer to us, and the dimmer star considerably more distant. He then began a catalogue of all the double stars he could find.

Herschel soon realised, as he expressed in a 1782 memoir, that the double stars he saw might be dependent; that one might be circling the other, following Newton's laws. In 1793 he began taking new readings of the position of the dimmer stars relative to their brighter neighbours. These observations verified his suspicion: some of the stars were indeed revolving slowly about their neighbour. In 1802 Herschel published his Catalogue of 500 new Nebulae ... and Clusters of Stars; with Remarks on the Construction of the Heavens. It was here that his discovery of the binary nature of some stars was announced.

Following Herschel's lead, other catalogues were made by other observers, such that--by the mid-1990s--over 60,000 binary stars have been catalogued. While most of these are out of reach of all but the largest of telescopes, hundreds of binaries are well within reach.

The visual binaries are arranged by constellation: 150 binaries with data about the Position Angle and Separation at J2000.0. The orbit of each of these binaries can be seen by clicking on the appropriate link.