The CFH12K camera, for use at the CFHT prime focus, is the largest
close-packed CCD mosaic camera in use today (2000) and saw first light
on the telescope in January 1999.
Not only does this camera cover
a large fraction of the sky with each exposure (42 by 28 arcminutes, or more
than 1.5 times the size of the full moon!) but its large number of pixels
(12,288 by 8,192: more than 100,000,000 pixels or 200 Megabytes of data per
image) provides a high angular sampling. With a 15 micron pixel size,
the scale at the prime focus (f/4) is 0.206 arc seconds per pixel, perfectly
adapted to properly sample the superb image quality of Mauna Kea (median seeing
at CFHT prime focus is 0.7 arcseconds). The camera is equipped with
twelve 2048x4096 pixel CCDs from the MIT Lincoln Laboratories. These
back-side illuminated CCDs provide significant increase in sensitivity,
in particular in the B band.
The camera was primarily designed and built by G. Luppino from the Institute
for Astronomy (University of Hawaii) with substantial assistance of CFHT
staff. CFHT was heavily involved in other areas of the
project: data acquisition system, data archiving, CCD controllers, auxiliary
electronics (for controlling the shutter, filter wheel, vacuum gauge,
temperature,...), as well as, camera characterization and improvements of the
CFHT prime focus to ensure the best optical conditions and reduction of
scattered lights.
CFH12K is a CFHT instrument fully suported for the
entire CFH community. CFHT is now working on a data reduction and
data evaluation pipeline (``Elixir'') that will produce optimal
calibrations and information to ensure the highest scientific return
from the data.
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