The telescope of the Stratospheric Observatory for Infrared Astronomy (SOFIA) is a airborne telescope. Capable of flying at a altitude of 12 kilometers. This capability makes it possible to fly above almost all the water vapor in the earths atmosphere. This makes it possible to observe infrared wavelengths that are normally absorbed.
The telescope is build inside the hull a adapted Boeing 747SP wide-body. The telescope is a Cassegrain reflector with primary mirror consists of 2,7m. The secondary mirror which is co-developed by TNO and Rsp, is a 352mm diameter mirror made out of a special alloy aluminium. Its greatly benefited from TNO’s manufacturing capability of aspheric and free form mirrors.