Development of an imaging fourier transform spectrometer for astronomy

Abstract

We present an overview of the past and current development of the Imaging Fourier Transform Spectrometer (IFTS) concept for ground telescopes produced in collaboration between ABB Bomem and Universite Laval. This instrument intends to produce spectra of variable resolutions up to R = λ/Δλ = 10 000 from the near UV to the near IR (350 nm to 900 nm). It is designed to fit the f/8 focus of the Mont Megantic 1.6m optical telescope in Quebec. The large number of spatial elements (> 1 million pixels) is the novel aspect of this FTS design along with innovative metrology system. Heritage from Next Generation Space Telescope (NGST) IFTS concept, Lawrence Livermore National Laboratory (LLNL)- ABB Bomem instrument and commercial ABB Bomem DA series FTS are reviewed. Techniques for accurately servoing the moving mirror alignment to a value smaller than 0.1 arc second and position to sub nanometer value are discussed. Also presented are results from the assembled interferometer sub-system.