  We report the discovery of an eclipsing cataclysmic variable with eclipse
depths > 5.7 mag, orbital period 94.657 min, and peak brightness V~18 at J2000
position 17h 25m 54s.8, -64d 38' 39". Detected by visual inspection of images
from Yale University's QUEST camera on the ESO 1.0-m Schmidt telescope at La
Silla, we obtained light curves in B, V, R, I, z and J with the SMARTS 1.3-m
and 1.0-m telescopes at Cerro Tololo and spectra from 3500 to 9000 Angstrom
with the SOAR 4.3-m telescope at Cerro Pachon. The optical light curves show a
deep, 5-min eclipse immediately followed by a shallow 38-min eclipse and then
sinusoidal variation. No eclipses appear in J. During the deep eclipse we
measure V-J > 7.1, corresponding to a spectral type M8 or later secondary,
consistent with the dynamical constraints. The estimated distance is 150 psec.
The spectra show strong Hydrogen emission lines, Doppler broadened by 600 -
1300 km/s, oscillating with radial velocity that peaks at mid deep eclipse with
semi-amplitude 500 +/- 22 km/s. We suggest that LSQ172554.8-643839 is a polar
with a low-mass secondary viewed at high inclination. No known radio or x-ray
source coincides with the new object's location.
