Each CCD array contains four back-illuminated MIT/Lincoln Laboratory CCID-80 devices. The detector assembly in each camera consists of a focal plane CCD array and associated electronics. Along with an internal stray light baffle, each lens assembly aperture is equipped with a hood to reduce scattered light from the Earth and Moon.
This corresponds to 1 detector pixel or 21 arcseconds (approx. Operating at nominal focus and a flight temperature of -75 degrees C, the 50% ensquared-energy half-width is 15 micron averaged over the FOV. The lens assemblies were designed for consistent image spot size across the field-of-view (FOV) and to produce undersampled images similar to Kepler. Each camera forms a 24×24 un-vignetted image on the detector in its focal plane.
All optical elements have antireflection coatings and one element has a long-pass filter coating to enforce a short-wavelength cutoff at 600 nm in the TESS bandpass.
The lens assembly has a 10.5 cm diameter entrance pupil and a focal ratio f/1.4. The lens assembly is a custom design housing seven lenses mounted into two separate aluminum barrels that are fastened together. Each camera consists of a CCD detector assembly, a lens assembly, and a lens hood. An overview of the FOV coverage and observing strategy for the mission can be found in the Operations page.
TESS is equipped with four identical refractive cameras with a combined field-of-view (FOV) of 24×96 degrees (known as an observing sector). The spacecraft provides power (via two deployable solar arrays), attitude control, data storage, and communications/transmission.Īrtist’s conception of the TESS spacecraft and payload. The payload is coupled to the spacecraft, an NGIS LEOStar-2/750 satellite bus. The TESS payload has a single instrument, a camera suite composed of 4 wide field-of-view optical cameras and their associated hoods, mount, sun shield, and Data Handling Unit (DHU). The TESS observatory consists of the spacecraft and the payload.
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