October 30, 1997

1
1SystemOverview
The University of Hawaii(UH) QUick Infrared Camera (QUIRC) utilizes a 1024 1024 pixel
HgCdTeAstronomical Wide Area Infrared Imaging(HAWAII)array produced by Rockwell Science
Center. This array is sensitive to radiation from 1to 2.5 m. The reimaging optics provide a 1:1
scale,giving the pixel scales listed in Table 1 for thevarious telescopes and configurations.
Table1. QUIRC pixel scales
Telescope Optics arcsec/pixel FOV (arcsec)
UH 88-inch f/10 0.1886 193x193
f/31 0.06084 62x62
CFHT f/8 0.150 154x154
0.61-m f/15 0.43 440x440
QUIST0.25m f/10 1.5 1550x1550
The QUIRCsystem is comprised of four functional components: (1)the detector, optics, and dewar;
(2)The detector readout electronics; (3) A DSP controller;and (4) the instrument control Sparcstation
and fiber optic communications interface. The first three components are phys ically integrated and
mounted on the telescope, while the fourth is typically located in the observing room and/or the
computerroom.
The QUIRC electronics are controlled from a Sparcst ation by issuing commands and receiving data
via fiber optic cables. The control program on the Sparcstation is called “qcdcom”. The qcdcom
program is based on the ccdcom program by M. Metzgerand was modified for use with QUIRC.
The qcdcomprogram controls taking exposures and writing data in FITS format to disk, operates the
movingparts of the instrument such as the shutter, filter wheel, and pupil mask, communicates with
the telescopeand guider to obtain information and perform mosaics, and providesa scriptcapability
for automaticallyperforming simple observing tasks. qcdcomis acommand line interface only and
does not directly provideimage display, but can be used with any popular display program that can
read FITS files (e.g. sao image, Vista, IDL). A link has also been provided to the viewfits program to
automaticallydisplay images (see below).
2 Near-Infrared Observing Techniques
Imaging in the near-infrared (1–2.5 m) generally requiresmore effort than at optical wavelengths,
because the background is so much higher. Thereare t wo general data reduction techniques in
commonuse—both of theserequire frequent observation of sky fields.
Thefirst data reduction philosophy is one in which the sky fields are usedfor subtraction, and the sky
subtractedimage is divided by normalized dome flats to removethe variations in quantum efficiency.
The advantageof this technique is that the dome lights have similar color temperature to the typical
sourcesbeing studied.
The second data reductiontechnique is one in which the sky exposures are also used as flats, so the
imageis sky subtracted, then divided by a normalized sky flat. This technique often will work better