A Fabry-Perot interferometer for ground-based millimetric spectroscopy

Astrophysical observations at millimeter and sub-millimeter wavelengths are one of the most useful tools to understand the history of the Universe. Although ground-based observations are affected by the presence of the Earth atmosphere, space telescopes remain limited in size offering only modest angular resolution not suitable to detect small spatial features of so compact objects. To date the ground-based solution seems to be the only feasible way to perform high angular resolution deep sky surveys. In this context a Fabry-Perot Interferometer (FPI) has been developed in order to improve the capabilities of MAD (Multi Array of Detectors), a 4-channel photometer optimized for multi-frequency observation of Sunyaev-Zel’dovich effect that will operate at Millimetre and Infrared Testagrigia Observatory (MITO), a 2.6-m in diameter telescope located in the Alps in Val d’Aosta (3480 m a.s.l.). The transmission response of an innovative system composed of two resonant metal grids in a FPI configuration is explored. A semi-empirical approach to perform an analysis of atmospheric transmission and emission at Dome C (Antartic Plateau) is suggested. The spectrometer CASPER2 (Concordia Atmospheric SPectroscopy of Emitted Ra- diation - MITO version) has been developed specifically to record atmospheric spectra assisting cosmological observations with the 2.6-m in diameter Cassegrain telescope at MITO.