Testing process for the WEAVE prime focus corrector lenses for the William Herschel Telescope - Observatoire de Paris Access content directly
Conference Papers Year : 2018

Testing process for the WEAVE prime focus corrector lenses for the William Herschel Telescope

Dijana Bogunovic
  • Function : Author
Graeme Jonas
  • Function : Author
Dave Cochrane
  • Function : Author
Andrew Rakich
  • Function : Author
Peter Connor
  • Function : Author
Abe Romeril
  • Function : Author
Jimi Romeril
  • Function : Author
Luke Gers
  • Function : Author
Eleanor Howick
  • Function : Author
Chris Young
  • Function : Author
Tony Reed
  • Function : Author
Ian Tosh
  • Function : Author
Émilie Lhomé
  • Function : Author
Kevin M. Dee
  • Function : Author
Gavin Dalton
  • Function : Author
Scott Trager
  • Function : Author
Jose Alfonso Lopez Aguerri
  • Function : Author
Antonella Vallenari
  • Function : Author
Esperanza Carrasco
  • Function : Author
Don Carlos Abrams
  • Function : Author
Kevin Middleton
  • Function : Author

Abstract

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.

Dates and versions

obspm-04072890 , version 1 (18-04-2023)

Identifiers

Cite

Dijana Bogunovic, Graeme Jonas, Dave Cochrane, Andrew Rakich, Peter Connor, et al.. Testing process for the WEAVE prime focus corrector lenses for the William Herschel Telescope. Proceedings of the SPIE, 2018, à renseigner, Unknown Region. ⟨10.1117/12.2312342⟩. ⟨obspm-04072890⟩
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