  Despite the continuing importance of ground-based parallax measurements, few
active programs remain. Because new members of the solar neighborhood tend
towards later spectral types, infrared parallax programs are particularly
desirable. Consequently, the astrometric quality of the new infrared camera,
FanCam, developed by the Virginia Astronomical Instrumentation Laboratory
(VAIL) for the 31-in (0.8-m) Tinsley reflector at Fan Mountain Observatory was
assessed using 68 J-band exposures of an open cluster, NGC 2420, over a range
of hour angles during 2005. Positions of 16 astrometric evaluation stars were
measured and the repeatability of those positions was evaluated using the mean
error in a single observation of unit weight. Overall, a precision of 1.3 +/-
0.7 microns in x (RA) and 1.3 +/- 0.8 microns in y (Dec) was attained, which
corresponds to 0.04" +/- 0.02" in each axis. Although greater precision is
expected from CCDs in the visual and near-infrared, this instrument can achieve
precision similar to that of the ESO NTT infrared parallax program. Therefore,
measuring parallaxes in the infrared would be feasible using this equipment. If
initiated, such a program could provide essential distances for brown dwarfs
and very low mass stars that would contribute significantly to the solar
neighborhood census.
