William Herschel
Telescope
The Aluminizing Plant
The plant was produced by Balzers
of Liechtenstein who subcontracted the large vacuum vessel to Grazebrook
Limited, a UK firm. The plant was installed in the WHT plant room and the
commissioning tests successfully carried out. During the aluminizing process,
a total of 63 g of aluminium is evaporated, 3.5 g being desposited on the
13m² surface of the primary mirror to create a reflective surface
100 nm thick. The power consumption of the plant rises to 85 KVA for the
90 seconds duration of the evaporating stage. Mirrors are aluminized once
a year or year and a half.
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