[3] The proposal for a Southern observatory in all likelihood originated among the same group of people who founded the Royal Astronomical Society in the United Kingdom.

[4] The official establishment of the Royal Observatory, Cape of Good Hope occurred on 20 October 1820[1] through an Order in Council of King George IV of the United Kingdom.

In accordance with its mandate, the principal activity of the Observatory was astrometry, and it was over its existence responsible for publishing many catalogues of star positions.

In the 20th century it turned in part towards astrophysics, but by the nineteen-fifties the city lights of Cape Town had rendered work on faint objects impossible and a new site in the Karoo semi-desert was sought.

The second HM Astronomer, Thomas Henderson, aided by his assistant, Lieutenant William Meadows, made the first observations that led to a believable stellar parallax, namely of Alpha Centauri.

[6][7] Around 1840, Thomas Maclear re-measured the controversial meridian of Nicolas-Louis de La Caille, showing that the latter's geodetic measurements had been correct but that nearby mountains had affected his latitude determinations.

[8][9] In 1882, David Gill obtained long-exposure photographs of the great comet of that year showing the presence of stars in the background.

[11] A later 20th-century HM Astronomer, H. Spencer Jones, was active in an international project for determining the solar parallax through observations of the minor planet Eros.

[20] They include: Historically, the main building contained a 10 feet focal length Transit by Dollond and a 6-feet Mural Circle by Thomas Jones.

It is the northern limit of the Western Leopard Toad (Bufo Pantherinus) and the only remaining natural habitat of the rare iris, Moraea aristata.