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Proceedings Paper

Ground-based and orbital off-axis aspherized grating imager-spectrographs: ISARD-OMP and OSIRIS-ODIN
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Paper Abstract

Progress in Active Optics Methods has led to the invention and production of blazed aspherical gratings. These developments use jointly 'vase form' submasters and a two-stage replication technique. It has been shown that the use of aspherized gratings greatly minimizes the number of optical surfaces. This improves the optical throughput of astronomical spectrographs and has a capability of correcting camera mirror aberrations up to f/1.2. With respect to refractive designs, the full achromaticity in correcting mirror aberrations by constant line spacing reflective gratings allows much broader spectral coverages -- hereafter [(lambda) (lambda) ] approximately equals 2 octaves. In addition, and also due to a full reflective design, such instruments provide quasi- constant spectral dispersions and are distortion free. These latter features increase the accuracy in the data reduction process (sky substraction, etc. ...), and are particularly convenient in the multi-aperture mode. Recent developments in this field are presented with imager-spectrograph ISARD, dedicated to the Cassegrain focus of the 2m Bernard Lyot Telescope at Pic-du-Midi Observatory for faint object studies in the optical domain [320 - 1200 nm], and with spectrograph OSIRIS, to be launched in a ODIN orbital mission in 1998 and built by the Canadian Space Agency for studies in the spectral range [295 - 800 nm].

Paper Details

Date Published: 9 July 1998
PDF: 14 pages
Proc. SPIE 3355, Optical Astronomical Instrumentation, (9 July 1998); doi: 10.1117/12.316804
Show Author Affiliations
Gerard R. Lemaitre, Observatoire de Marseille/Univ. de Provence Aix-Marseille (France)
Eric Harvey Richardson, Univ. of Victoria (Canada)


Published in SPIE Proceedings Vol. 3355:
Optical Astronomical Instrumentation
Sandro D'Odorico, Editor(s)

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