  This document presents the results from our spectroscopic survey of Halpha
emitters in galactic and SMC open clusters with the ESO Wide Field Imager in
its slitless spectroscopic mode. First of all, for the galactic open cluster
NGC6611, in which, the number and the nature of emission line stars is still
the object of debates, we show that the number of true circumstellar emission
line stars is small. Second, at low metallicity, typically in the Small
Magellanic Cloud, B-type stars rotate faster than in the Milky Way and thus it
is expected a larger number of Be stars. However, till now, search for Be stars
was only performed in a very small number of open clusters in the Magellanic
Clouds. Using the ESO/WFI in its slitless spectroscopic mode, we performed a
Halpha survey of the Small Magellanic Cloud. 3 million low-resolution spectra
centered on Halpha were obtained in the whole SMC. Here, we present the method
to exploit the data and first results for 84 open clusters in the SMC about the
ratios of Be stars to B stars.
