VTD Vakuumtechnik Dresden GmbH
Niedersedlitzer Straße 75
01257 Dresden

Phone:+49 351 - 2805-0
Fax:+49 351 - 2805-240

Archive / 2009 / #19

The world's largest reflecting telescope with a touch of Saxony.

The 10.4 m Gran Telescopio Canarias, currently the world's largest reflecting telescope, has now been officially put into operation far above the clouds of La Palma. It is a joint Spanish-Mexican project ... with a Saxon touch.

The main mirror consists of 36 hexagon elements made with the utmost precision out of a glass-ceramic material. An extremely thin and highly uniform coating of ultra-pure aluminium was deposited on to these elements in order to create a mirror. The plant required for this task was developed by VTD Vakuumtechnik Dresden.

However, the actual coating work was performed at the telescope's place of installation. For this reason, the very compact coating plant had to be taken up the arduous path to the telescope's mountain location and installed there. Why all this effort? With the glass-ceramic elements coming from Germany one would have thought there would be an easier way of doing it. Their reflective coating is, however, exposed to the weather every day and wears away over time. These elements thus have to be newly coated at regular intervals to maintain the telescope's performance. This is best done on site for several reasons and this is why the Saxons were able to make a not insignificant contribution to this impressive project.

Since last year a mirror coating plant from VTD GmbH has also been in operation in the Azerbaijani Caucasus. But that is another story, albeit far above the clouds too ...

2009, VTD Vakuumtechnik Dresden GmbH