Paper 13099-5
Paper 13099-5
HARMONI at ELT: modelling the optical performance of a diffraction limited integral field spectrograph
On demand | Presented live 16 June 2024 
Abstract
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 470 nm to 2450 nm with resolving powers from 3300 to 18000 and spatial sampling from 60 mas to 4 mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. To model the optical performance we include manufacturing and alignment tolerances alongside other static and dynamic effects. Diffraction of both image and pupil become significant when the spectrograph slit width matches the diffraction limited point spread function. A set of Zemax OpticStudio macros and Python scripts are used to bring together the subsystem models that make up HARMONI and combine them to include all these effects. We present an overview of our approach to modelling this complex instrument and key results predicting the optical performance of HARMONI.
Presenter
UK Astronomy Technology Ctr. (United Kingdom)
Stephen Todd leads the Applied Optics Group at the UK Astronomy Technology Centre in Edinburgh. As Lead Optical Engineer on the HARMONI project for the ELT he works with optical designers from across the consortium and with the instrument Systems Engineering team. He has worked on a number of integral field spectrographs over his career, staring with UIST on the UK Infrared Telescope as part of his PhD. Since then, he has worked on KMOS for the VLT and METIS for the ELT. Projects outside astronomy have included medical imaging (optical design and technical leadership of a device to detect and measure the early stages of Age-related Macular Degeneration), Earth Observation and Quantum Key Distribution.