Nemeth/Star Productions - Picture Gallery

Welcome to the first episode of SPACE-FRIDAY: Photography in 2025 and Happy New Year to our audience. Today we take you to a journey to the Hartebeesthoek Radio Astronomy Observatory, short HartRAO, in the valley of the Magaliesberg hills, 75 kilometers north-west of Johannesburg in South Africa. The HartRAO is one site of space operations of the SARAO, the The South African Radio Astronomy Observatory. The HartRAO was originally established by NASA as Deep Space Station 51 to get data from, and send commands to several unmanned US space missions such as Ranger, Surveyor and Lunar Orbiter spacecrafts, which landed on the Moon or mapped it from orbit, the Mariner missions, which explored the planets Venus and Mars, and the Pioneers, which measured the Sun’s wind. The HartRAO homes an 85-foot (26- m) diameter antenna, a 15-m radio telescope (called the eXperimental Demonstrator Model) and a new 13.2-m VLBI Global Observing System (VGOS) antenna stands ready for action and will join the geodetic VLBI endeavors once equipped with the requisite receiver. NASA and Roskosmos also home control stations at the HartRAO. In 1975, the station was handed over to the South African Council for Scientific and Industrial Research (CSIR), which converted it to a radio astronomy observatory. The 26-m radio telescope at HartRAO has played a key role in the development of VLBI in the Southern Hemisphere and has participated in astrometric VLBI observations since the 1980s. Astrometry involves the precise measurements of the positions and movements of celestial objects. Extragalactic source positions are measured in the radio domain using networks of radio telescopes spread throughout the planet and operating jointly in interferometric mode. This so-called VLBI technique has allowed scientists to synchronise antennas across continents into a super telescope the size of the earth to measure the angular direction of compact AGNs with a part per billion accuracy (~100 µas), about the angular size of a 2-Rand (or 1-Euro) coin placed in Australia as seen from South Africa. The HartRAO 26-m radio telescope has been participating in roughly monthly, 24-hour K-band CRF observing sessions over the past seven years, in conjunction with other overseas telescopes in the array, including the Hobart and Mopra telescopes in Australia, the Yebes telescope in Spain, the Korean VLBI Network (KVN) of telescopes, and the Very Long Baseline Array (VLBA) of telescopes in the USA (see figure to the left). Because of its unique geographical location and being part of the only long southern baseline, which is essential for measuring celestial latitude, the 26-m telescope has been a crucial component of the K-band CRF. One of the ongoing technical developments is the VLBI observing mode for MeerKAT, in collaboration with JIVE (Joint Institute for VLBI ERIC) in the Netherlands and a group of local and international stakeholders. Recently, so-called “fringes” were successfully recorded in joint experiments with telescopes in Europe and at HartRAO. In 1988, the observatory became a national facility operated by the Foundation for Research Development (FRD), which became part of the NRF in 1999. Initially, the function of HartRAO was purely research in radio astronomy, but in the 1980s a new application called Space Geodesy (geodesy using space techniques) was implemented at HartRAO. SARAO was established in 2017 by the Minister of Science and Technology as a national facility within the NRF as the institutional successor to the SKA SA Telescope Project and to continue the work of HartRAO. The SKA Project South Africa and the HartRAO are now organized under one unit and the site is officially called “The Hartebeesthoek Site of NRF|SARAO". Text: Nemeth/Star Productions and SARAO 20th Anniversary report Thank you very much to the HartRAO, SARAO and NRF for making our visit possible. All pictures licensed: CC-BY 4.0 Please credit as follows Photo: Sven Nemeth Published by: Nemeth/Star Productions (https://nemethstarproductions.eu)