Robert Thorburn Ayton Innes FRSE FRAS (10 November 1861 – 13 March 1933) was a Scottish astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars. He was also the first astronomer to have seen the Great January Comet of 1910, on 12 January. He was the founding director of a meteorological observatory in Johannesburg, which was later converted to an astronomical observatory and renamed to Union Observatory. He was the first Union Astronomer. Innes House, designed by Herbert Baker, built as his residence at the observatory, today houses the South African Institute of Electrical Engineers.
He was born on 10 November 1861 in Edinburgh to John and Elizabeth (née Ayton) Innes. He had 11 younger siblings.
A self-taught astronomer, he went to Australia at an early age and made his living as a wine merchant in Sydney, where, using a home made 12-inch reflecting telescope, he discovered several double stars new to astronomy. Innes published a double star catalog in 1900 that assimilated all earlier observations by southern astronomers, to provide the longest baseline for orbit determination. He published another in 1927. His catalogs were in turn incorporated into later catalogs of all known double stars. He also published some papers on perturbations in Mars' and Venus' orbits.
Despite having had no formal training in astronomy, he was invited to the Royal Observatory, Cape of Good Hope by the HM Astronomer Sir David Gill in 1894 and appointed in 1896. While at the Cape, he discovered what is now known as Kapteyn's Star which the latter had listed as one of a number included in the Cordoba Durchmusterung but missing from the later Cape Photographic Durchmusterung. Innes found what had happened to it: it has a very large proper motion and had moved considerably during the intervening time interval.