The Enhanced Resolution Imager and Spectrograph for the VLT

¹ Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany
e-mail: davies@mpe.mpg.de
² INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5., 50125 Firenze, Italy
³ INAF - Osservatorio Astronomico d’Abruzzo, Via Mentore Maggini, 64100 Teramo, Italy
⁴ INAF - Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
⁵ STFC UK ATC, Royal Observatory Edinburgh, Blackford Hill. Edinburgh EH9 3HJ, UK
⁶ ETH Zurich, Institute of Particle Physics and Astrophysics, Wolfgang-Pauli-Strasse 27, 8093 Zurich, Switzerland
⁷ Leiden Observatory, University of Leiden, PO Box 9513, 2300 RA Leiden, The Netherlands
⁸ European Southern Observatory, Karl-Schwarzschildstr. 2, 85748 Garching, Germany
⁹ I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
¹⁰ European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago, Chile
¹¹ Space Sciences, Technologies, and Astrophysics Research Institute, Université de Liège, 4000 Sart Tilman, Belgium
¹² LESIA, Observatoire de Paris, PSL, CNRS, Sorbonne Université, Université de Paris, 5 Place Janssen, 92195 Meudon, France
¹³ Centre for Astronomy, Dept. of Physics, National University of Ireland Galway, University Road, Galway H91 TK33, Ireland

Received: 31 March 2023
Accepted: 24 April 2023

Abstract

The Enhanced Resolution Imager and Spectrograph (ERIS) is an instrument that both extends and enhances the fundamental diffraction limited imaging and spectroscopy capability for the VLT. It replaces two instruments that were being maintained beyond their operational lifetimes, combines their functionality on a single focus, provides a new wavefront sensing module for natural and laser guide stars that makes use of the Adaptive Optics Facility, and considerably improves on their performance. The observational modes ERIS provides are integral field spectroscopy at 1–2.5 μm, imaging at 1–5 μm with several options for high-contrast imaging, and long-slit spectroscopy at 3–4 μm. The instrument is installed at the Cassegrain focus of UT4 at the VLT and, following its commissioning during 2022, has been made available to the community.