Far-Infrared Interferometric Experiment (FITE): Toward the First Flight

FITE is a far-infrared interferometer on board balloon. In the far-infrared wave region, the spatial resolution is generally limited by the diffraction limit resolution of the primary aperture of a telescope. FITE is a Fizeau type interferometer with the baseline of 8 m corresponding to 4 arcsecond at 150 microns. The foci of the two parabola mirrors coincide at the primary focus that must be located at the input diaphragm of the cold optics in the cryostat. The two beams make an interference fringe at the focal plane. In December, 2008, the first launch of FITE was planned in Brazil as a collaboration between Japan and Brazil. FITE was assembled and checked out about its performance. However, the launch was postponed to 2010 due to unsuitable weather condition.