It will be possible to digitize the large collection of variable
stars spectra (Be stars). The data baseBeSS, available at LESIA,
provides a catalogue of all known (~2000) Be stars and owns (~130 000)
available spectra of these objects. The study of the long-term
spectroscopic variability of Be stars is very
important to understand their sporadic
ejection of matter. At the present time, the
data start only in 1990 and the analysis of
plates from 1950 to 1980 will enlarge the time
series of data and will allow to detect a period
in the ejections.