Optical design of the camera for Transiting Exoplanet Survey Satellite (TESS)

The optical design of the wide field of view refractive camera with a 34 degree diagonal field for the TESS payload is described. This fast f/1.4 cryogenic camera, operating at -75°C, has no vignetting for maximum light gathering within the size and weight constraints. Four of these cameras capture full frames of star images for photometric searches of planet crossings. The optical design evolution, from the initial Petzval design, takes advantage of Forbes aspheres to develop a hybrid design form. This maximizes the correction from the two aspherics resulting in a reduction of average spot size by sixty percent in the final design. An external long wavelength pass filter has been replaced by an internal filter coating on a lens to save weight, and has been fabricated to meet the specifications. The stray light requirements are met by an extended lens hood baffle design, giving the necessary off-axis attenuation.