Scottish astronomer who, as royal astronomer at the Cape of Good Hope (1831–33), was the first to measure the parallax of a star (Alpha Centauri). He withheld the announcement of his findings until 1839, a few months after both Friedrich Bessel and Friedrich Struve had received credit for first measuring stellar parallaxes.

Henderson was elected a fellow of the Royal Astronomical Society (1832), the Royal Society of Edinburgh (1834), and the Royal Society of London (1840). Upon his return from the Cape of Good Hope in 1834, he was appointed the first Astronomer Royal of Scotland, professor of astronomy at the University of Edinburgh, and director of Calton Hill Observatory.