Bibcode
Bogunovic, Dijana; Jonas, Graeme; Cochrane, Dave; Rakich, Andrew; Connor, Peter; Romeril, Abe; Romeril, Jimi; Gers, Luke; Howick, Eleanor; Young, Chris; Reed, Tony; Tosh, Ian; Lhomé, Émilie; Dee, Kevin M.; Dalton, Gavin; Trager, Scott; Aguerri, J. A. L.; Bonifacio, Piercarlo; Vallenari, Antonella; Carrasco, Esperanza; Abrams, Don Carlos; Middleton, Kevin
Referencia bibliográfica
Proceedings of the SPIE, Volume 10700, id. 107003A 6 pp. (2018).
Fecha de publicación:
7
2018
Número de citas
2
Número de citas referidas
0
Descripción
A new prime focus corrector for the WEAVE project for the William
Herschel Telescope is being produced. The corrector consists of six lens
elements, the largest being 1.1 m in diameter. It also incorporates an
Atmospheric Dispersion Corrector. Testing procedures for the WEAVE prime
focus corrector lens elements are described here. Critical issues
encountered in practice, including the influence of the lens size, wedge
and weight on the testing procedure are discussed. Due to large lens
dimensions, a dedicated test tower and lens support system has been
developed to measure the optical surface form errors of the concave
surfaces and the transmitted wavefront of each lens. For some of the
lens elements, sub-aperture measurements have been performed using an
off-axis Hindle sphere and the resultant OPD maps have been stitched
together. The challenge of testing a wedged lens with a combination of a
long radius convex surface and a short radius concave surface has been
resolved by using another lens from the system as an auxiliary lens. The
practice of testing convex surfaces via internal reflection/transmission
through the lens element has been avoided entirely in this case and some
discussion justifying the choices of metrology approach taken is given.
The fabrication and acceptance testing of the lens elements has been
completed within the expected time and budget, and all elements have
been shown to meet requirements.