  A new, inexpensive polarimetric unit has been constructed for the Dominion
Astrophysical Observatory (DAO) 1.8-m Plaskett telescope. It is implemented as
a plug-in module for the telescope's existing Cassegrain spectrograph, and
enables medium resolution (R~10,000) circular spectropolarimetry of point
sources. A dual-beam design together with fast switching of the wave plate at
rates up to 100Hz, and synchronized with charge shuffling on the CCD, is used
to significantly reduce instrumental effects and achieve high-precision
spectropolarimetric measurements for a very low cost. The instrument is
optimized to work in the wavelength range 4700 - 5300A to simultaneously detect
polarization signals in the H beta line as well as nearby metallic lines. In
this paper we describe the technical details of the instrument, our observing
strategy and data reduction techniques, and present tests of its scientific
performance.
