4MOST is a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's 4m-VISTA telescope at Paranal, Chile. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle that positions 2436 science fibres in the focal surface of which 1624 fibres go to two low-resolution optical spectrographs (R = λ/Δλ ~ 6500) and 812 fibres transfer light to the high-resolution optical spectrograph (R ~ 20,000). Currently, almost all subsystems are completed and full testing in Europe will be finished in spring 2023, after which 4MOST will be shipped to Chile. An overview is given of instrument construction and capabilities, the planned science of the consortium and the recently selected community programmes, and the unique operational scheme of 4MOST.
The new era of Multi-Object Spectrograph (MOS) Survey projects, in particular WEAVE (on the WHT at the ING) and 4MOST (on VISTA at ESO Paranal), require complex data flow systems. These systems encompass the software development for target selection, fibre configuration and observation at the telescope front-end and spectral processing, spectral analysis and archiving at the back-end. The system must also include quality control procedures, signaling mechanisms and alert reporting to ensure optimal use of telescope time and scientifically robust data products. Key to ensuring a fully functioning data flow system by first light are Operational Rehearsals (OpR) which use simulated data in end-to-end tests of the entire system. The Cambridge Astronomical Survey Unit (CASU) has been integral in defining and coordinating these OpR efforts, in its role of providing the back-end data management and the spectral processing pipelines, for both WEAVE and 4MOST. The WEAVE OpR programme is complete and we await first light. The first two rehearsal stages (OpR1 and OpR2) of the 4MOST OpR programme are complete while the third, and most complex, stage will commence in 2022.
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.
A status overview of 4MOST is presented, a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's VISTA telescope at Paranal. Its key specifications are: a large field of view of 4.4 deg2 and a high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs (R = λ/Δλ ~ 6500), and 812 fibres transferring light to the high-resolution spectrograph (R ~ 20 000). The 4MOST system integration has commenced and the selection process for ESO community survey programmes has been started. This overview presents the expected performance of the instrument, the science the consortium expects to carry out, and the unique operational scheme of 4MOST.
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.
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.
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