An image-stabilizing camera has been constructed at the Dominion Astrophysical Observatory, in collaboration with the University of Montreal and the Canada-France-Hawaii Telescope (CFHT) Corporation, for use at the prime focus of CFHT. This instrument incorporates a fast guider to follow image motion and a "smart" shutter to reject periods of image degradation. An aperture wheel is also available to study the improvement in image quality made by stopping down the entrance aperture of the camera. The design and performance characteristics of the instrument are reviewed here.

The Canada.Fraxxe-Hawajj Telescope (GHT) is developing an Adaptive Optics Instrument Adaptor for general use at its 3.6 m telescope. It consists of a 19 electrode, bimcrph deformable mirror (1:6:12) used with a 19 sub-aperture, curvature wavefront sensor. The wavefront sensor optical gain is controlled by the amplitude of a vibrating membrane mirror, which produces a defocus in t1 pupil plane. The tip-tilt correction is accomplished separately from the high order correction by tI f/19.6 reimaging mirror of the adaptor. The optical design minimizes tI number of reflections by using off-axis mirrors. The whole assembly is contained in an aluminium casting 1 10 cm in diameter and 28 cm thick. The adaptive optics control system will provide a 90 Hz servo bandwidth and modal control. The Pegasus user interface will manage overall control of tl system by the observer. This user-friendly interface has been developed at FHT, tl goal being to allow non-specialists in adaptive optics to operate the instrument in an optimal fashion, given the numerous parameters such as: brightness of t.l reference source, iscplanatic angle between reference and scieree sources, speed of atmospheric turbuleixz, wavelength of observation etc. Various imaging detectors or more complex instruments can be mounted on this adaptive optics adaptor. in t1 initial stage, we plan to use a CU) camera and NICMOS (HgCdTe) array for imagery in tl visible and non-tlrmal infrared. An integral field spectrograph will be provided as well The latter will offer a great deal of observing mode flexibility; imagery and/or spectroscopy with various combinations ci spatial and spectral resolution. . PROJECF STATUSThe Canada-Fraixe-Hawajj Telescope has undertaken the development and fabrication of an Adaptive Optics Bxmnette (AOB) for its 3.6 m telescope on top of Mauna Kea (Hawaii). The "bomtte" will be installed at tl f/8 Cassegrain focus of tl telescope. Physically, the bonnette is an adaptor ring 1.1 m in diameter and 28 cm thick on which varions instruments (imagers, spectrographs) can be mounted. It will be a fiity instrument, offering varions backup modes to insure reliability frcxn an operational point of view. The user interface aims at being reasonably straightforward, offering a simple and restricted choice of parameters to tJ user.The design and fabrication tasks are shared between many institutes; the CFHT is managing tl project, issuing the specifications, supervising development and fabrication, performance modelling and realizing the general user interfe. The Dominion Astrophysical Observatory (DAO, Canada) has designed and is fabricating the opto-mechanical bench, and the wavefront sensor assembly (WFS). The optical design is from H. Richardson (U. of Victoria Canada) and DAO is subcontracting the fabrication of the optics to various companies in the US and Canada. The company Laserdot (Marcoussis, France) is providing the deformable mirror and the real-time control system. Laserdot is also providing some high level software tools. The fabrication o...

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In 1989, a project was funded by the Canada-France-Hawaii Telescope Corporation to construct a coudé spectrograph with an f/4 camera and capable of using a 30 by 60-cm echelle grating as well as the three 30-cm gratings used now with the existing f/8 spectrograph.Construction cost is kept very low for a spectrograph of such large aperture by avoiding both large corrector lenses and a full-aperture cross disperser. The grating blaze efficiency is near optimum because the deviation angle (between the collimator and camera axes) is small, the camera mirror being located far from the grating next to the collimator. The echelle grating has 316 grooves/mm thus comparatively wide free spectral regions, which eases the problem of preventing overlapping orders. The disadvantage is that the spectral coverage of each order exceeds both the dimensions of available Reticon or CCD detectors and the angular coverage of the spectrograph camera. Thus the spectrograph is not suited to survey work where many spectral regions are recorded simultaneously. Its advantage is its efficiency, both optically and financially, in recording a selected spectral region at high resolution. The order sorting variablewedge grism is located in the diverging beam after the slit and moves the spectrum perpendicular to dispersion in order to center it on the detector. The camera, whose monochromatic focal ratio ( i.e. for a given spectral line) is f/4, consists of a parabolic concave mirror followed by a relatively small triplet corrector lens. The central element is combined with a right-angle reflecting prism which reflects the converging beam down out of the incident light to the detector package whose dimensions are not then limited by considerations of obstruction of light by the detector package.