Product category:
Cameras and imaging systems
News Release from: Optical Surfaces | Subject: Astronomical optics
Edited by the Laboratorytalk Editorial
Team on 13 May 2005
French observatory buys UK optics
Components will enable researchers to extend the capabilities of the observatory's 1.93 metre telescope to observe astroseismological phenomena and extrasolar planets
The Observatoire de Haute-Provence (St Michel, Marseille, France) has purchased a series of high precision optics from Optical Surfaces The optical components including spherical mirror, Schmidt plate, perforated flat and a cross dispersing prism form the key elements of a high-resolution (70,000) Schmidt camera system which will enable researchers to extend the capabilities of the observatory's 1.93 metre telescope to observe astroseismological phenomena and extrasolar planets
This article was originally published on Laboratorytalk on 28 May 2008 at 8.00am (UK)
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The camera is an f3.6 folded Schmidt design to be used with the Sophie echelle grating working from 387nm to 696nm.
Having previously supplied similar optics for a series of astrophysics groups including the Wyffos, Feros and Narval projects, Optical Surfaces says it was selected for its proven record in manufacturing, mounting and testing demanding high precision spectrograph optics.
To achieve the required resolution the Schmidt camera incorporated a 500mm diameter spherical mirror (1400mm radius) manufactured from Zerodur and surface finished to a uniform lambda/10p-v.
Further reading
Off-axis parabolic mirrors are large and accurate
Optical Surfaces can typically produce off-axis parabolic mirrors up to 600mm in diameter with surface accuracy to lambda/20p-v depending upon off-axis angles
Optical reference flats are high precision
Optics up to 450mm diameter are provided with a Fizeau interferometric test report, while larger flats are quality assured using the Ritchey-Common test procedure
Made from BK7 glass, the Schmidt plate supplied was a 320mm diameter aspheric optic designed to depart from spherical by 50 microns.
Measuring only 25mm thick, the Schmidt plate required a detailed knowledge of polishing flexible optics.
In addition, Optical Surfaces has supplied a 220x270mm cross dispersing prism that sits in front of the echelle grating and a 440mm diameter Zerodur flat mirror specially machined with two irregularly shaped holes to allow the CCD camera and the fibre optics to operate through it.
Sophie will be the new spectrograph aimed at replacing the current Elodie design.
The new spectrograph will use the radial velocity technique, which allowed the discovery of the first extrasolar planet ten years ago.
Drawing upon the high quality of the supplied component optics, Sophie should achieve a total throughput of 5 to 10%, depending upon operating resolution and measurement wavelength.
Offering approximately three orders of magnitude better throughput and higher resolution than the current spectrograph, the observatory is looking to widen the star sample currently observed, detect fainter planetary objects, and spectroscopically observe planetary atmospheres as well as galactical structures.
Optical Surfaces ISO 9001-2000 approved manufacturing facility provides the flexible resources to supply from single specialist requirements to OEM quantity high precision optics and optical systems.
All optics and optical systems are provided with a complete quality test assurance report.
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