Proceedings Article | 25 August 2022
Encarnaci Romero Colmenero, Petri Väisänen, Lisa Crause, Danièl Groenewald, Christian Hettlage, Alexei Kniazev, Rudolph Kuhn, Moses Mogotsi, Enrico Kotze, Rosalind Skelton, Lee Townsend, Solohery Randriamampandry, Elizabeth Naluminsa, Thea Koen, Veronica Van Wyk, Xola Ndaliso, Anja Schroeder, Nhlavutelo Macebele, Chaka Mofokeng
KEYWORDS: Optical spectroscopy imaging, Telescopes, Observatories, Astronomy, Near infrared, Spectrographs, Large telescopes, Imaging spectroscopy, Spectroscopes
SALT is a 10-m class optical telescope located in Sutherland, South Africa, owned by an international consortium and operated in fully queue-scheduled mode by the South African Astronomical Observatory. In this paper we present an update on all observatory performance metrics since the start of full science operations in late 2011, including science time, weather and technical downtime, and time used for planned engineering activities and commissioning. We analyze key statistics describing the science output of SALT, the completion fractions of scheduled observations and programs per priority class, and analyze the more than 400 refereed papers to date since first light based on SALT data. We discuss our latest telescope metrics and the results of our analysis of acquisition times, what steps we are taking to make significant improvements to our metrics such as virtual visits to the HET, new quick-look software and queue scheduler, the development of a new metrics dashboard and pre-positioning of the guide probes. We also discuss the usage of the SALT Data Archive and plans to ensure compatibility with the Virtual Observatory. Some of these projects, along with the latest developments in software, instrumentation and engineering projects, are presented in detail in other SPIE papers. The SALT refereed paper output has increased steadily since 2017 - when counted from the start of science operations, we show that the trend is still following other 6-10 m observatories (when scaled by the number of telescopes). When scaled by operations costs (where known), SALT is still clearly very cost-effective compared to most other large telescope operations. Our main workhorse instrument, the RSS spectrograph, still produces the largest number of papers and dominates our best conditions queue (i.e. dark time, best seeing, photometric conditions). HRS publications have been steadily increasing since its arrival in 2016, with the HRS having essentially taken over the bright moon and poorer conditions queue. Spectropolarimetry has also become a more widely used mode. Our Fabry-Pérot system, though, has fallen victim to Covid19 and is still awaiting repairs. We also discuss the exciting arrival to SALT of the Near IR spectrograph, which achieved first light on sky on the 8th July 2022, and our strategic vision for transient and exoplanet science in the near future. Within this context, we will briefly update on the HRS High Stability mode and MaxE, our generation 1.5 instrument, and on our plans for SALT as an important component of the SAAO in an "Intelligent Observatory" framework, which aims to network a suite of telescopes and instruments on SAAO's observing site.
