Cunningham, MH;
Doel, P;
Brooks, D;
Brynnel, J;
De Jong, RS;
Frey, S;
Schroeck, M;
... Barden, SC; + view all
(2023)
Assembly and alignment of the 4-metre multi-object spectroscopic telescope wide field corrector.
Journal of Astronomical Telescopes, Instruments, and Systems
, 9
(1)
, Article 15002. 10.1117/1.JATIS.9.1.015002.
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Abstract
The 4-metre multi-object spectroscopic telescope (4MOST) is a fiber-fed multi-object spectrograph for the VISTA telescope at the European Southern Observatory (ESO) Paranal Observatory in Chile. The goal of the 4MOST project is to create a general purpose and highly efficient spectroscopic survey facility for astronomers in the 4MOST consortium and the ESO community. The instrument itself will record 2436 simultaneous spectra over a 1/44.2 square deg field of view and consists of an optical wide-field corrector (WFC), a fiber positioner system based on a tilting spine design, and three spectrographs giving both high and low spectral dispersion. The WFC comprises of six lenses grouped into four elements, two of which are cemented doublets that act as an atmospheric dispersion corrector. The first lens element is 0.9 m in diameter while the diameter of the other elements is 0.65 m. For the instrument to meet its science goals, each lens was aligned to be well within 1/4100 μm - a major challenge. This was achieved using contact metrology methods supplemented by pencil beam laser probes. In particular, an off-axis laser beam system has been implemented to test the optics' alignment before and after shipment. This work details the alignment and assembly methods and presents the latest results on the achieved lens positioning and projected performance of the WFC.
| Type: | Article |
|---|---|
| Title: | Assembly and alignment of the 4-metre multi-object spectroscopic telescope wide field corrector |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1117/1.JATIS.9.1.015002 |
| Publisher version: | https://doi.org/10.1117/1.JATIS.9.1.015002 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | wide-field multi-object spectrograph facility; visible and infrared survey telescope for astronomy; wide field corrector; 4-metre multi-object spectroscopic telescope |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10168654 |
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