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ING instrumentation update 2018-2019

This page reports the current status of the instrumentation plans for the WHT and INT.

In semester 2017A began a series of changes in the availability of instrumentation at the WHT and INT, driven by the upcoming commissioning of new instruments at both telescopes. The information below will help you to make the most of the evolving observing opportunities driven by the schedules for these instruments.

We welcome your questions, comments or requests for clarification. Please email Chris Benn, ING Head of Astronomy ( or me (

Marc Balcells
ING Director
Updated to 4th May 2018

Changes at the WHT

  1. New survey instrument and new telescope control system. Current plans call for the integration and commissioning of the WEAVE multi-fibre and multi-IFU spectrograph in mid-2019, with the WEAVE surveys beginning in autumn 2019. The manufacture of WEAVE is currently well-advanced, and some sub-systems (e.g. the spectrograph) are nearly completed.

    During 2018, the WHT TCS (control electronics and low-level software) will be upgraded.

  2. Technical stand-down periods. A number of stand-down periods linked to WEAVE preparation and to the deployment of the new TCS are being scheduled during 2018 and 2019. The dates of the standdowns will to some extent depend on when hardware components are delivered. We will keep the TACs well-informed about these changes, in order that the best possible use can be made of the time available.

    During final integration and commissioning of WEAVE in 2019, science observations will pause for a period of 2 to 3 months.

  3. AF2. AF2 is no longer offered, and the enclosure (GHRIL) formerly occupied by the AF2 spectrograph is being remodelled to accommodate the WEAVE spectrograph. Only in the event of a significant delay to WEAVE would AF2 be offered again.

  4. WHT PF imaging. The WHT's PFIP prime-focus imager (16-arcmin field of view) is no longer offered. The main optical imaging options at the WHT are now ACAM (8-arcmin field of view) and visiting instrument PAUCam (~40-arcmin field of view), which is available to the ING community.

  5. Nasmyth visitor instruments. Visitor instruments requiring a Nasmyth focus (including those instruments formerly deployed in the GHRIL enclosure) can be deployed in the GRACE Nasmyth enclosure. Teams proposing to observe with Nasmyth visitor instruments in 2018B and later semesters need to communicate with the observatory to ensure any required changes are understood and agreed well in advance.

  6. Time distribution and instrumentation in the WEAVE surveys era. We remind users that the start of the WEAVE surveys will mark the transition of the WHT from a classical observing telescope to a mainly survey telescope. We will retain 30% as open time for allocation by the TACs. The instrumentation offered in open time will be WEAVE, ISIS, LIRIS, ACAM and visitor instruments (including PAUCam). For visitor instruments the Cassegrain, GRACE and prime focal stations will be available. At prime, only the 40 arcmin corrector will be available for visitor instruments; mounting visitor instruments on the WEAVE corrector would require an additional instrument rotator and cable wrap, and this is not envisioned for a number of years at least.

    Given the complexity of mounting and dismounting WEAVE, the current plan is to change to other instruments every 9 - 12 months, and we will investigate observing modes which will maximise open time accessibility to all RAs. The dates of the periods when the WHT will not be devoted to WEAVE surveys will be agreed upon by the ING Board in consultation with the TACs and the Director's science advisory committee (SAC).

Changes at the INT

  1. HARPS3. ING has reached an agreement with the Cambridge-led THE (Terra-Hunting Experiment) Consortium for the deployment at the INT of HARPS3, a high-resolution stabilised spectrograph which will conduct a 10-year survey aimed at discovering Earth-mass planets in Earth-like orbits around the nearest G and K-type dwarf stars. The THE Consortium will carry out a full upgrade of the INT to allow for remote or robotic operation. 50% of the INT time will be devoted to the THE survey, the remainder being available as open time to be allocated by the TACs.

  2. Downtime. The dates for the INT upgrade will be announced once the project calendar is known. Tentatively, a six-month downtime for the upgrade may be scheduled in late 2019, with the HARPS3 instrument arriving after that.

  3. Instrument availability. Current schedules suggest that WFC and IDS will remain available until at least 2019A, and probably during 2019B as well. The instruments will be mothballed once the telescope upgrade starts; the use of the INT prime focus is incompatible with the cadence requirements of HARPS-3 surveys. We are exploring routes for a second INT instrument to co-exist at the Cassegrain focus with the HARPS-3 fibre pick-up unit. This might be a general-purpose, ACAM-lookalike camera-spectrograph. There are as yet no plans or funding for this second instrument.

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