Controlling the world's largest telescope
Observatory Sciences Ltd, a scientific software consultancy based in Cambridge UK, has been awarded a contract from the US Association of Universities for Research in Astronomy (AURA) to produce the software that will control the world's largest solar telescope.
The Advanced Technology Solar Telescope (ATST) will have a 4m diameter primary mirror and be sited at an altitude of 10,000ft (about 300m) on the summit of Haleakala ('House of the Sun') on the Hawaiian island of Maui. The total construction budget for the project is US$298m.
Observatory Sciences' contract covers the production of the ATST Telescope Control System software. At the heart of this is multi-axis motion control of the servo drives in the telescope mount, which requires monitoring changes in atmospheric temperature, pressure and humidity, to accurately set the altitude and azimuth of the telescope to observe the Sun. Many telescope sub-systems are coordinated by the software, such as the dome, cooling systems, primary and secondary mirror positioning and wave-front sensor systems.
Philip Taylor of Observatory Sciences said: “With such a large mirror pointing directly at the Sun, cooling of the equipment is a major issue for this project and dedicated thermal management is provided for each of the telescope subsystems.”
The ATST project is a collaboration of nearly all of the American institutions involved with solar physics and is run by the United States National Solar Observatory (NSO) based in Tucson, Arizona. When completed, in 2017, it will be the largest telescope in the world dedicated to observing the Sun, with unprecedented abilities to view solar detail and allow scientists to learn even more about the Sun and solar-terrestrial interactions.
“Although the primary aims of the project are scientific,” said Taylor, “studies such as mapping magnetic fields around the Sun relate to sun spots and the solar cycle. This knowledge will help predict variability, advance understanding of climate change as well as solar flares, which can affect both aircraft and space satellites.”
ATST's 4m primary mirror will feed an advanced array of instruments designed to study the Sun at wavelengths from near ultraviolet into the far infra-red. High-order adaptive optics techniques, developed by the NSO, will correct blurring of solar images caused by Earth's atmosphere. This will allow scientists to observe features in the solar atmosphere with unprecedented sharpness, down to structures only a few tens of kilometres in size. Its unique design is optimised to allow precise measurements of solar magnetic fields, particularly under circumstances where they have been previously invisible, allowing us to understand and predict solar variability.
Observatory Sciences has been involved in the development of software for the ATST since 2004. The Telescope Control System will be responsible for the control of the telescope's positioning and image quality. It will operate a number of associated telescope subsystems and will utilise the ATST Common Services software that provides a framework for the development and deployment of ATST software throughout the observatory.