Optical system of the SOFIA Telescope

Hermann Bittner; Matthias Erdmann; Barbara Herdt; Armin Steinacher

doi:10.1117/12.324474

28 August 1998 Optical system of the SOFIA Telescope

Hermann Bittner, Matthias Erdmann, Barbara Herdt, Armin Steinacher

Proceedings Volume 3356, Space Telescopes and Instruments V; (1998) https://doi.org/10.1117/12.324474
Event: Astronomical Telescopes and Instrumentation, 1998, Kona, HI, United States

Abstract

The optical system of the airborne SOFIA telescope consists of a Cassegrain telescope with an effective aperture of 2.5 m and a so-called Nasmyth focus providing a lateral focus exit with access from the cabin side. The central optical part of the SOFIA Telescope is the 2.7m primary mirror made from a solid block of Zerodur as a monolithic element. The mirror will be lightweighted by making it to a dedicated 'double-arch' shape and by milling hexagonal holes from the backside. The lightweighting factor will be approximately 80 percent yielding a mirror mass of 850 kg only. The secondary mirror has a high-performance chopper actuator enabling an efficient background suppression especially for far IR observations. The tertiary mirror is implemented as a dichroic beamsplitter transmitting the visible part of the incoming radiation. This part is fed by an additional mirror to one of the tracking images, the focal plane imager, which allows a high-precision pointing of the star field under observation in the sub-arcsecond range. The two other imagers, the wide field imager and the fine field imager, are boresighted to the main telescope and will be used for the acquisition of the star field as well as for pointing and tracking of the telescope. The paper presents the current status of the development of the optical system including the imagers.

Citation Download Citation

Hermann Bittner, Matthias Erdmann, Barbara Herdt, and Armin Steinacher "Optical system of the SOFIA Telescope", Proc. SPIE 3356, Space Telescopes and Instruments V, (28 August 1998); https://doi.org/10.1117/12.324474

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