Design of Reflective Three Mirror Anastigmat Telescope

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Abstract

Supporting Materials

Abstract

The primary objective of this research is to develop optical and opto-mechanical design procedures for reflective optical systems. Challenges in fabrication, metrology and assembly have limited the surfaces used in such systems to rotationally symmetric surfaces. Freeform surfaces or non-rotationally symmetric surfaces can significantly increase the performance for a fixed volume or keep the same performance with 20% less volume. To gain familiarity with optical and opto-mechanical design techniques, two systems were studied: a two mirror Ritchey-Chrétien telescope and a Three Mirror Anastigmat (TMA). The two mirror Ritchey-Chrétien telescope using rotationally symmetric hyperbolic surfaces was designed and built. The optomechanical design incorporated an external tube to align the primary and secondary mirrors in the axial, radial and tilt directions. The TMA achieves better performance because of the addition of a third mirror. Both off-axis conic sections and freeform mirrors were considered in the design. The opto-mechanical design developed the telescope frame and the fiducial surfaces that relate the optical surfaces to each other and to the detector. The TMA exhibited impressive performance (< 2% of the error in the RC telescope) using freeform surfaces.

Three-mirror anastigmat frame stress analysis

TMA Raytrace

Supporting Materials

• Design tools for Free-Form Optics

The following faculty, students, and PEC affiliates are involved in this project: