  We describe the specifications, characteristics, calibration, and analysis of
data from the University of New South Wales Infrared Fabry-Perot (UNSWIRF)
etalon. UNSWIRF is a near-infrared tunable imaging spectrometer, used primarily
in conjunction with IRIS on the AAT, but suitable for use as a visitor
instrument at other telescopes. The etalon delivers a resolving power in excess
of 4000 (corresponding to a velocity resolution ~75 km/s), and allows imaging
of fields up to 100" in diameter on the AAT at any wavelength between 1.5 and
2.4 microns for which suitable blocking filters are available.
