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James Webb Space Telescope
TFI: Tunable Filter Imager

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The TFI is a sensitive camera that shares the optical bench of the FGS. It provides JWST with the capability of imaging a 2.2' x 2.2' field-of-view over a wavelength range of 1.5 - 5.0 µm, with a non-functional region between 2.5 and 3.2 µm. The filters are characterized by spectroscopic resolving powers of 75 to 120 for central wavelengths selected by the user. The TFI can also perform imaging with a choice of four coronagraphs as well as a non-redundant mask.