CFHT operating manual - Homepage Usask

CFHT Observatory Manual - Observatory (Sec.5) http://www.cfht.hawaii.edu/Instruments/ObservatoryManual/CFH...
To accommodate the changes in focal length of the telescope with
temperature, and the focus position changes induced by the various
filters, the camera must be able to move along the optical axis of the
telescope. The focus stage assembly (FSA) accommodates this motion,
supporting the camera and its shutter on a motorized stage bolted on top
of the upper end platform. In order to follow the apparent motion of the
sky due to the Earth’s rotation, two small cameras fix on stars outside of
the field of view, providing automatic guidance of the telescope and
measurements of the focal changes.
MegaCam
At the heart of MegaPrime is MegaCam, a unique camera built by the
"Département d’Astrophysique, de Physique des Particules, de Physique
Nucléaire et de l’Instrumentation Associée" at the French
"Commissariat à l’Energie Atomique" (CEA). In addition to a cryostat
housing the mosaic, and its cryogenics system to maintain it cold, CEA
built the camera shutter, the filter jukebox and the electronics to acquire
the image and send it to a computer through fiber optics cables.
AOB/PUEO with KIR
The Adaptive Optics Bonnette (AOB), also called PUEO after the sharp vision
Hawaiian owl, was developed for the Canada-France-Hawaii Telescope, based on
F.Roddier’s curvature concept. The ‘‘bonnette’’ (adaptor) is a facility instrument
mounted at the f/8 Cassegrain focus of the CFH 3.6 m telescope on top of Mauna Kea
(Hawaii). The instrument is the result of a collaborative effort between several
institutes : The CFHT (managing the project and designing the general user
interface); The Dominion Astrophysical Observatory (Canada) who designed and
fabricated the opto-mechanical bench, the curvature wavefront sensor and its
electronics; the company Cilas (France) who provided the deformable curvature
mirror and the Real Time Computer and software, including a high level maintenance
interface; the Observatoire de Paris-Meudon (France) who manufactured the separate
tip-tilt mirror and was in charge with the final integration, testing and calibration of
the instrument. The UH adaptive optics team provided guidance throughout the
project. The system was commissioned at CFHT during three runs in the first
semester 1996.
KIR is a high resolution 1024 x 1024 near-infrared camera based on the Rockwell
Science Center HAWAII (HgCdTe Astronomical Wide Area Infrared Imaging) focal
plane array. This array is sensitive to radiation from 0.7 to 2.5 microns. KIR has been
designed to be used at the F/20 output focus of PUEO, the CFHT Adaptive Optics
Bonnette (AOB). It consists in an LN2 cryostat which harbors the detector, the fixed
0.67:1.0 transfer optics, an F/20 cold stop and a filter wheel. The standard I, J, H, K
and K’ broad-band filters are available, as well as several narrow-band filters. A
preamplifier and a shutter are mounted externally to the dewar. The system is driven
by an SDSU/Leach CCD controller which is the controller commonly used at CFHT
for all visible and infrared detectors. The system provides the observers with a user
interface , called DetI, incorporated into the CFHT/Pegasus observing environment,
through which they will configure the camera, control the data acquisition, monitor
the data storage and do some pre-processing.
The Dewar has been constructed by the Universite de Montreal, part of the array DSP
code by the Observatoire Midi-Pyrenees. The acquisition system and software were
under the responsability of CFHT. The final integration of the science grade detector
has been carried out at CFHT. The first light has been obtained during the first
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