  We describe a technique to identify Be stars in open clusters using Stromgren
b, y, and narrow-band Halpha photometry. We first identify the B-type stars of
the cluster using a theoretical isochrone fit to the (b-y, y) color-magnitude
diagram. The strongest Be stars are easily identified in a (b-y, y-Halpha)
color-color diagram, but those with weaker Halpha emission (classified as
possible Be star detections) may be confused with evolved or foreground stars.
Here we present such photometry plus Halpha spectroscopy of members of the
cluster NGC 3766 to demonstrate the accuracy of our technique. Statistical
results on the relative numbers of Be and B-type stars in additional clusters
will be presented in a future paper.
