3: The telescope NOT
The telescope NOT was built 1984 as a cooperation between Denmark, Sweden, Norway and Finland.
Later in 1997 Iceland also participated.
The budget was 3 million Euro.
The first observations could start 1990.
NOT replaced the telescopes at Saltsjöbaden's observatory which you can read about here:
|Weight of moving parts:
|Weight of telescope tube
|fov, field of view:
||30' (about the size of moon)
NOT's mirror of 2.5 meters rests on air cushions.
These airbags are set under air pressure and the mirror's shape is monitored and corrected continuously over time.
It corrects the mirror's shape as it deforms differently depending on the angle at which the telescope is pointing.
The telescope's bearing in the horizontal axis is a thin film of oil so that no metal to metal contact occurs.
NOT's mechanical installation was constructed by the Swedish company Bofors
who usually produces big cannons.
The motors are hydraulic and without gears, they use friction wheels instead.
With only hydraulics it makes a cool design which is good when observing in the infrared range.
Because of all the clouds over our observation pass I had time to study the technical drawings and documentation deeply.
One interesting thing according to the reports is that fiber optic cables leaking IR radiation and interferes with the sensors.
Test measurements showed that it was only the cables with black plastic skin that blocked the IR leak.