A study of composite spectrum stars (coll. J.-M. Carquillat and N. Ginestet, OMP) associate the imaging and spectroscopic modes of PISCO. Some stars exhibit the signature of a composite spectrum which could be interpreted as the sum of (at least) two spectra of different type. (Ginestet et al., 1994) The aim of this program is to detect the possible presence of a companion and then to identify the spectral type of both components either with color indices or (when possible) with a spectrum with high angular resolution which would separate the spectra of the individual stars.
Such a program is well suited to the qualification of the spectroscopic mode of PISCO.