Calibration at elevation of the WEAVE fibre positioner

TL;DR

This paper details the calibration procedures and recent maintenance of the WEAVE fibre positioner, ensuring precise fibre placement for the spectrograph at the William Herschel Telescope.

Contribution

It provides an overview of calibration, maintenance, and modifications to improve the accuracy and reliability of the WEAVE fibre positioner system.

Findings

Fibre systems inspected and repaired

Flexure modifications implemented

Calibration procedures updated

Abstract

WEAVE is the new wide-field spectroscopy facility for the prime focus of the William Herschel Telescope in La Palma, Spain. Its fibre positioner is essential for the accurate placement of the spectrograph's 960 fibre multiplex. We provide an overview of the recent maintenance, flexure modifications, and calibration measurements conducted at the observatory prior to the final top-end assembly. This work ensures that we have a complete understanding of the positioner's behaviour as it changes orientation during observations. All fibre systems have been inspected and repaired, and the tumbler structure contains new clamps to stiffen both the internal beam and the retractor support disk onto which the field plates attach. We present the updated metrology procedures and results that will be verified on-sky.