1997PASP..109..821G

We present the first results using infrared arrays, devices which do not employ charge coupling, in a new "drift scanning" mode to significantly increase the area of the sky which can be surveyed, especially in the high background 3-5 \mm bands. Even with fast electronics, wide field imaging in the thermal IR is difficult due to the high backgrounds. Often, only a sub-array of the frame can be readout before saturation. Drift scanning allows this sub-array to be a long narrow strip which is stepped perpendicular to the long side, by allowing the telescope to track at non-sidereal rates, and then a mosaic is constructed in the computer memory in real time. The method has been implemented with the UCLA Twin-Channel Infrared Camera system which employs two different classes of arrays. One is the NICMOS 3 HgCdTe array and the other is an SBRC InSb array; both detectors have 256\xx256 pixels. Using a drift rate of 1 arcminute/minute on the Shane 3-m telescope at Lick Observatory, we are able to survey about 180 square arcminutes per hour at two wavelengths simultaneously (e.g. J,K or H,L). Limiting magnitudes are typically J=15, L= 12. Data reduction methods are described and observations of the globular cluster M3, the star forming region M17, and the Moon are used as illustrations.