Interstellar dust spectral index: a balloon-borne experiment

A balloon-borne experiment has been conceived in order to map the sub-millimetric galactic emission at four different wavelengths between 400 μm and 2 mm at an angular scale of 1°. Such measurements will make it possible both to investigate the nature of the interstellar dust and to disentangle the galactic contribution from extragalactic and cosmological signals. A binocular telescope system has been realized by means of two 37 cm of-axis wobbling parabolic mirrors, each one coupled with a two-channel 3He photometer. The first trans-Mediterranean flight is scheduled for summer 1995.