A Tunable Echelle Imager
  We describe and evaluate a new instrument design called a Tunable Echelle Imager (TEI). In this instrument, the output from an imaging Fabry-Perot interferometer is cross-dispersed by a grism in one direction and dispersed by an echelle grating in the perpendicular direction. This forms a mosaic of different narrow-band images of the same field on a detector. It offers a distinct wavelength multiplex advantage over a traditional imaging Fabry-Perot device.   Potential applications of the TEI include spectrophotometric imaging and OH-suppressed imaging by rejection. 
I. K. Baldry and J. Bland-Hawthorn