ELT-HIRES the high resolution spectrograph for the ELT: phase-A design of its polarimetric unit
Abstract
The Phase A study for the high-resolution spectrograph for the Extremely Large Telescope (ELT-HIRES) has been concluded in late 2017. We present the main outcome for a polarimetric light feed from the intermediate focus (IF) and a Nasmyth focus of the telescope. We conclude that the use of the IF is mandatory for high-precision spectropolarimetry. Among the description of the product tree, we present phase-A level opto-mechanical designs of the subunits, describe the observational and calibration modes, the PSF error budget, and the preliminary FEM structural and earthquake analysis. An update on the development of a ray tracing polarimetric simulator to estimate the instrumental polarization including both the telescope mirrors and the optical elements of the polarimeter is reported. Trade-off strategies and ongoing solutions in view of the Phase B are outlined too.
- Publication:
-
Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III
- Pub Date:
- July 2018
- DOI:
- 10.1117/12.2312115
- Bibcode:
- 2018SPIE10706E..1YD