Welcome to the South African Astronomical Observatory (SAAO), South Africa’s leading astronomy research institute and home to the Southern African Large Telescope, the largest optical telescope in the southern hemisphere.

Founded in 1820, the SAAO is the national centre for optical and infrared astronomy in South Africa. Its primary role is to conduct fundamental research in astronomy and astrophysics by providing a world-class facility to scientists. The SAAO also promotes astronomy and astrophysics in southern Africa, by sharing research findings and discoveries, and participating in outreach activities to enthuse citizens about physics and astronomy.

The SAAO is a facility of the National Research Foundation, which operates under the South African Department of Science and Technology. The SAAO is comprised of headquarters in the eponymous suburb of Observatory in Cape Town, and a dedicated research and observation station with several working telescopes (including SALT) outside the Karoo town of Sutherland in the Northern Cape.

In order to achieve the best possible observing conditions, all of the current astronomy operations occur in Sutherland. Historical telescopes in Cape Town are still regularly used for outreach and public events.

Find out about visiting Cape Town or Sutherland

History of the SAAO

On the 20th of October 1820, the British King George IV authorised the British Admiralty to establish a Royal Observatory at the Cape of Good Hope in order to provide accurate star positions to assist ships navigating the treacherous waters of the Cape. It was from this observatory that the current SAAO formed, and the suburb of Observatory, Cape Town, took its name.

The SAAO has roots in other parts of the country as well. The present South African Astronomical Observatory was formed in 1972 by combining the Royal Observatory at the Cape with the Republic Observatory in Johannesburg. The three most modern telescopes from the two observatories found a new home on a small plateau outside Sutherland with dark skies and perfect weather for astronomical observations. The SAAO also procured the Radcliffe Observatory telescope in Pretoria (the largest in the southern hemisphere at the time) which was installed in Sutherland in 1974.

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Today’s SAAO

Since 1972, SAAO astronomers have benefited from the dark, unpolluted skies of the Karoo, with little to no heavy cloud cover to negatively affect observing. Research has ranged from planetary studies to the nature and life-cycle of stars and galaxies both near and far.

Explore the SAAO's Sutherland Facilities in VR

Work on stars whose size and light vary resulted in the International Astronomical Union (IAU) sponsoring a conference on these variable stars in Cape Town in 1995 – the first IAU conference ever to meet in Africa. SAAO researchers have also helped us to understand the centre of our own galaxy, using infrared cameras and detectors to pierce the thick dust clouds that hide the centre from view. The SAAO’s contributions to the study of nearby galaxies made it logical that the first IAU Symposium in Africa, on galaxies in the Local Group, should also meet in Cape Town in 1998.

Cape Town will also host the 32nd General Assembly of the IAU in 2024. This will be the first time in the 105 year history of the IAU that the General Assembly will be held on the African continent. The award recognises the incredible strides that African astronomy has taken in recent years.

New instruments and techniques have kept the telescopes at the SAAO internationally competitive. SAAO now hosts The Southern African Large Telescope (SALT) which was constructed in 2005, has been performing scientific observations since 2011, the largest optical telescope in the southern hemisphere with a maximum diameter of 11 metres.

View SALT in more detail

The SAAO grounds in Cape Town were declared a South African National Heritage Site in 2018, recognising the incredible achievement on the site and their significance over the past two centuries, and will ensure this heritage is preserved. The site has also been recognised by a UNESCO case study as a potential Astronomical World Heritage Site.

Ecology and Environment

The SAAO headquarters in Cape Town is situated on a 9ha property on a small hill, within the Two Rivers Urban Park (TRUP) in Observatory. The park is located where the Black and Liesbeek Rivers meet and was originally chosen to be within view of Table Bay, to allow visual time signalling to visiting ships.

The property is one of the last remaining locations close to the city centre where the original ecology of the area is preserved. The property is central to the Two Rivers Urban Park, a conservation area established by the City of Cape Town. It is bordered to the east and north by wetlands, and the low-lying areas are prone to flooding in winter.

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Before it was acquired for the observatory, the landscape was rocky, treeless and windswept, but supported a remarkable variety of seasonal grasses and bulbs. No longer barren, over the nearly two centuries of its existence, the site has been planted extensively with shrubs and trees to act as windbreaks.

The Two Rivers Urban Park supports a wide range of bird and animal life and a variety of flowering bulbous plants. The observatory property marks the northern limit of the Western Leopard Toad (Amietophrynus pantherinus), an endangered species, and is the only remaining habitat of the rare iris Moraea Aristata.