Published online by Cambridge University Press: 05 January 2006
CASPER (Concordia Atmospheric SPectroscopy of Emitted Radiation)is a spectrometer proposed for installation at Dome C, devoted tomeasurements of atmospheric emission in the spectral regionbetween 180 μm and 3 mm (3–55 cm-1). Thisinstrument will be able to perform continuous spectral sampling atdifferent altitudes at angular scales of ~1°. From therecorded data it is possible to extract atmospheric transmittancewithin 1% in the whole wide operating band, together with watervapour content and O2 and O3 concentrations. CASPER willallow us to characterize the site for future FIR/mm telescopes.Atmospheric data recorded by CASPER will allow for correction ofastrophysical and cosmological observations without the need fortelescope-specific procedures and further loss of observation timewith more precision in the observations themselves. Calibration ofground-based telescopes on known sky sources is strongly affectedby atmospheric absorption. CASPER has this as its primary goal.The spectrometer is based on a Martin-Puplett interferometer. Twodata sampling solutions will be performed: phase modulation &fast scan strategy. Sky radiation is collected towards theinterferometer by an optical setup that allows the field of view,to explore the full 0° ÷ 90° range of elevation angles. Witha low spurious polarization instrument, monitoring of polarizedatmospheric contribution will be possible.