HARMONI at ELT: Design & Test on the current status of Low Order Wavefront Subsystem Pick Off Arm Engineering Model (LPOA-EM)
Abstract
HARMONI is the first-light, adaptive-optics-assisted, near-infrared integral field spectrograph for the ELT, covering 800 to 2450 nm with resolving powers from 3000 to 7000. The Low Order Wavefront Sensor subsystem (LOWFS) provides field stabilisation by measuring the motion of the instrument focal plane relative to the telescope wavefront sensors. Following a rescope process in 2025, LOWFS has been updated to operate three LOWFS Pick-Off Arms (LPOA) simultaneously within a shared volume. We present first results from the LPOA Engineering Model (EM) characterisation campaign on two rotary joints, shoulder and elbow, including measurements of angular resolution, discrete step tracking validated by independent metrology, rotation axis wobble, and radial and axial runout of the bearing assembly.
Keywords
Cite
@article{arxiv.2607.22227,
title = {HARMONI at ELT: Design & Test on the current status of Low Order Wavefront Subsystem Pick Off Arm Engineering Model (LPOA-EM)},
author = {Iago Funes Vecino and Guillermo Mercant Rubio and Alonso Álvarez Urueña and Laura García Moreno and Gonzalo José Carracedo Carballal and Irene M. Ferro Rodríguez and Heribert Argelaguet Vilaseca and Javier Piqueras López},
journal= {arXiv preprint arXiv:2607.22227},
year = {2026}
}
Comments
8 pages, 10 figures, SPIE Astronomical Telescopes + Instrumentation 2026