Description
We have used the Two Micron All Sky Survey and Palomar Observatory Sky Survey photographic plates, digitized by the US Naval Observatory's Precision Measuring Machine program, to derive proper motions over a 100 square degree, spatially complete region centered on the Praesepe open cluster. Proper-motion measurements spanned the magnitude range R~12-19, which covers most of the lower main sequence in Praesepe. The incidence of H{alpha} emission from moderate-resolution (~2600), red spectroscopy of 434 faint candidate members and 126 field control stars demonstrates that ~60%-80% of candidates within 2{deg} of the cluster center are genuine Praesepe members.
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