Telescope Coating Plant


The VISTA telescope at the European Southern Observatory Paranal site in the Atacama desert Chile required an upgrade to the mirror coating plant. The mirrors are coated using a magnetron sputtering process. The old system could only work with two targets and needed upgrading to work with Silver, Aluminium and Silicon so that new recipes could be used to improve mirror performance.


We worked closely with the UK Astronomy Technology Centre to develop a new gas supply cabinet providing controlled supplies of Argon, Oxygen and Nitrogen gas. A new control cabinet was developed to be added to the existing Profibus network and the Siemens S7 PLC code was updated to support the additional gasses and the addition of a new magnetron. Development and testing of the new gas cabinet was carried out in our workshop and the new cabinet was then shipped to Chile – followed by 2 engineers from PTLA. Our engineers spent 3 weeks on site installing and testing the upgrade. Working at the Paranal site had its own challenges due to the high altitude and dry atmosphere. Static was a significant concern, and extra care had to be taken to protect the electronics against ESD. The introduction of Oxygen gas was also a significant change, and care had to be taken to minimise the additional fire risks posed.


The upgraded coating plant enables enhanced mirror cleaning and new mirror coatings for the VISTA telescope – which will help the European Southern Observatory imaging the skies for years to come.