Summary

• The WHT will be entirely devoted to WEAVE in 2024. WEAVE LIFU mode, both low and high resolutions, is being offered in open time in semester 2024B. Open-time access to each of the WEAVE modes will be offered after commissioning for that mode is completed.
• The INT is not being offered in semester 2024B. INT regular observations with WFC and IDS stop in June 16th 2024, when the telescope closes down for upgrades and HARPS3 deployment.

Introduction

This page reports the instrumentation plans for the WHT and INT.

During 2024, the ING plans to complete a series of changes in the availability of instrumentation at the WHT and INT, driven by the deployment of new instruments on both telescopes.

WHT

1. WEAVE. Regular science observations with the new WEAVE multi-fibre and multi-IFU spectrograph started in October 2023. Observations used the LIFU modes (low as well as high spectral resolutions), and they will continue throughout 2024. Commissioning of the MOS and mIFU modes is making good progress. After each WEAVE mode is successfully commissioned, a science verification programme is carried out. This is followed by the start of science surveys and open-time access for that mode.

2. Time distribution and instrumentation in the WEAVE surveys era. We encourage WHT users to read the WHT telescope time document in

   http://www.ing.iac.es/astronomy/whttime.html.

   In summary, the start of WEAVE science operations marks the transition of the WHT from a classical observing telescope to a service, queue-driven operation, with a 70%--30% split between surveys and open time, after provision is made for 5% ITP.
   Given the complexity of mounting and dismounting WEAVE, the availability of other instrumentation in open time is under discussion. Observers can safely assume that WEAVE will be continuously mounted on the WHT for the coming 2 years.

Changes at the INT

1. HARPS3. The Cambridge-led THE (Terra-Hunting Experiment) Consortium is making steady progress in the construction of HARPS3 for deployment at the INT. HARPS3 is a high-resolution stabilised spectrograph which will conduct a 10-year survey aimed at discovering Earth-mass planets. The THE Consortium is carrying out a full upgrade of the INT to allow for robotic operation. Half of the INT time will be devoted to the THE survey, the remainder being available as open time (most likely for robotic observations with HARPS3) to be allocated by the TACs.

2. Timeline. The INT upgrade is scheduled to start on 17th June 2024, and the HARPS3 first light to be in early 2025.

3. HARPS3 open time. Good progress with the HARPS3 instrument suggests we may be able to offer HARPS3 in open time in semester 2025B.

We welcome your questions, comments or requests for clarification. Please email Marc Balcells, ING Director (director@ing.iac.es) or Chris Benn, ING Head of Astronomy (crb@ing.iac.es).

Updated to 15th August 2023