Page 33 - EngineerIT Nov-Dec 2025

INDUSTRY NEWS

SALT marks 20 years of

astronomical achievement

By Hans van de Groenendaal, Science and technology writer*

ALT, often called “Africa’s giant helped confirm heavy element The partnership behind SALT
eye on the sky,” remains the synthesis models in the merger SALT is owned by the SALT Foundation,
Slargest single optical telescope ejecta, marking a breakthrough in a private company registered in
in the Southern Hemisphere and one multi-messenger astronomy. South Africa. Shareholders include
of the largest in the world. Its 11 m universities, research institutes and
segmented mirror allows astronomers 2019: Exoplanet microlensing funding agencies across Africa,
to detect light from distant objects SALT contributed to an international India, Europe and North America. The
that are a billion times too faint to be campaign using gravitational National Research Foundation (NRF)
seen with the unaided eye. microlensing to detect new is the largest shareholder with about
exoplanets. Its spectroscopy one-third of the equity and covers
The idea for SALT emerged in the late supported the characterisation of a just over half of SALT’s operating
1990s when South African scientists short-period exoplanet discovered budget. The size of each partner’s
put forward a bold proposal to by the Korean Microlensing shareholding determines their access
build a 10 m class optical telescope Telescope Network, highlighting to telescope time.
as a flagship for the new South SALT’s strength in rapid follow-up
Africa. In June 1998, the government observations. Major partners include:
committed US$10 million (about 3 • Rutgers University
million rand at the time) to turn this Eight super-hot stars identified • Nicolaus Copernicus Astronomical
into reality. Using SALT’s ultraviolet-sensitive Centre (Polish Academy of
spectroscopy, astronomers Sciences)
Construction at the Sutherland site discovered eight new extremely hot • Dartmouth College
in the Northern Cape was completed sub-dwarf stars, each exceeding • University of Wisconsin–Madison
in 2005. After commissioning and 100 000 K in surface temperature. • Inter-University Centre for
performance verification from 2006 These rare objects offer insight into Astronomy and Astrophysics (India)
to 2009, SALT entered full scientific late-stage stellar evolution. • Smaller partners include the
operations in September 2011. American Museum of Natural
Since then, it has steadily built a The “Peekaboo” galaxy History and the UK SALT Consortium,
track record of major astronomical SALT helped analyse a tiny nearby currently representing Armagh
milestones. galaxy nicknamed the Peekaboo Observatory.
Galaxy, which recently emerged
Sutherland was selected for its from behind a fast-moving star.
ABOUT THE NRF
altitude, clear skies, semi-arid SALT’s spectra showed extremely low
The National Research Foundation
conditions and minimal light pollution. metallicity, similar to early Universe
is an independent statutory body
The telescope sits 1 800 metres above galaxies, offering a rare local
mandated to support and promote
sea level, far from major cities and glimpse into primordial conditions.
research in South Africa. Its work
atmospheric interference.
includes funding, human capital
2023: Quadruple star system
development, maintenance of
Scientific milestones In collaboration with the University
national research facilities, public
2017: First multi-messenger event of Canterbury, SALT confirmed
engagement in science and
(GW170817) the gravitational binding of a
strengthening the national science
SALT was among the first telescopes four-star system with two pairs of
system to support government
to observe the optical afterglow of close-orbiting stars. The discovery
priorities.
the first detected neutron star merger. provides a valuable testbed for
Website: www.nrf.ac.za
The early spectrum it captured understanding multi-star formation.
33 | EngineerIT November/December 2025