We present an update on the overall integration progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now scheduled for first light in early-2021, with almost all components now arrived at the observatory. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been implemented to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 mini integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000.
We present an update on the overall construction progress of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations, and some detailed end-to-end science simulations that have been effected to evaluate the final on-sky performance after data processing. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project has experienced some delays in procurement and now has first light expected for the middle of 2019.
KEYWORDS: Control systems, Spectrographs, Databases, Telescopes, Human-machine interfaces, Data acquisition, Picture Archiving and Communication System, Calibration, Observatories, Sensors
WEAVE is the next-generation spectroscopic facility for the William Herschel Telescope (WHT) 1,2. WEAVE offers multi-object (1000 fibres) and integral-field spectroscopy at two resolutions (R ~ 5000, 20000) over a 2-deg field of view at prime focus and will mainly provide follow up of ground-based (LOFAR) and space-based (GAIA) surveys.
The Observatory Control System (OCS) is responsible for providing the software control and feedback framework through which WEAVE will be operated. This paper summarizes the design of the different OCS subsystems and the interfaces between them and other WEAVE components.
In the remainder of this paper, Section 2 outlines the other WEAVE systems with which the OCS interacts, Section 3 describes the system architecture, Section 4 comments on system-architecture decisions, Section 5 describes the main components of the OCS, Section 6 outlines the life-cycle of an OCS Observing Block and, finally, Section 7 gives an overview of the OCS testing plan.
The Observation Queue Scheduler (OQS) for WEAVE is described in this paper, with particular emphasis on the scheduling algorithm. WEAVE is the new 2-deg field of view multi-object (1000 multiplex) spectroscopy facility (R5000 and R20000) at the 4.2-m William Herschel Telescope. The OQS helps to maximize the scientific impact of WEAVE observations by optimising the schedule of the observing blocks, taking into account the science priority, required instrument configuration and observing constraints. On a nightly basis the OQS will assist the observer in creating a flexible queue of suitable observing blocks to be executed. It will be also possible to run a version of the OQS for extended periods of time to provide guidance on the longer-term planning of WEAVE surveys.
WEAVE is the next-generation spectroscopic facility for the William Herschel Telescope (WHT), offering multi-object (1000 fibres) and integral-field spectroscopy at two resolutions (R ~ 5000, 20000) over a 2-deg field of view at prime focus. WEAVE will (mainly) provide optical follow up of ground-based (LOFAR) and space-based (GAIA) surveys. First light is expected in mid 2018. Here, we describe the calibration unit, which will be adapted from an existing unit for the AF2+WYFFOS spectrograph (WEAVE's precursor) at the WHT. We summarise the results from a thorough characterisation of current performance (e.g. intensity, stability and focal-plane coverage of illumination as a function of lamp type and wavelength). We then set out our plans for upgrading the unit and its control systems to meet the WEAVE science and operational requirements. We conclude from this assessment that the upgraded AF2+WYFFOS calibration unit will meet the requirements for WEAVE. The design of the WEAVE calibration unit is now complete.
We present the Final Design of the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT), together with a status update on the details of manufacturing, integration and the overall project schedule now that all the major fabrication contracts are in place. We also present a summary of the current planning behind the 5-year initial phase of survey operations. WEAVE will provide optical ground-based follow up of ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single (dual-beam) spectrograph, with total of 16k spectral pixels, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project is now in the manufacturing and integration phase with first light expected for early of 2018.
The scientific productivity of complex instrumentation strongly depends on the availability of data-reduction pipelines. In the case of AF2+WYFFOS, the multi-object one-degree field-of-view fibre-fed spectrograph at the 4.2 m William Herschel Telescope (WHT), the full scientific exploitation of the data has often been slowed down because of the non-availability of a pipeline. A dedicated pipeline has been developed to overcome this. Running in IDL, it performs full reduction of AF2+WYFFOS data: fibre-to-fibre sensitivity corrections, fibre tracing, wavelength calibration, optimal extraction, sky subtraction.
AF2+WYFFOS is the multi-object one degree field-of-view fibre-fed spectrograph at the prime focus of the 4.2 m
William Herschel Telescope (WHT) at the Observatorio del Roque de Los Muchachos (ORM). Demand for this has been
decreasing over the years due to its low overall throughput. Given the strategic importance of multi-fibre spectroscopy
for the WHT’s future, with the coming of WEAVE (the powerful next-generation multi-object spectrograph for the
WHT to be commissioned in 2017), during 2013 and 2014 ING staff carried out an end-to-end analysis of the reasons for
low throughput. The investigations addressed target-acquisition/positioning/guiding, focal-plane geometry, optical
transmission and overall system throughput measurements.
AF2+WYFFOS performance has improved significantly as a result of these enhancements, and it is ready now to
perform as a useful precursor and science test-bed for surveys with WEAVE, the new wide-field multi-object
spectroscopy facility at the WHT.
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