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Image above: Top view of the spectrograph, NOVA’s primary contribution to WEAVE,  showing both low-resolution and high-resolution optical paths (left) and the main units (right). © NOVA

WEAVE is a multi-object spectrometer and multi-integral-field-unit (IFU) facility at the William Herschel Telescope (WHT) on La Palma. It utilises a large new prime focus corrector providing a 2-deg diameter field with a pick-and-place fiber positioner system hosting 1000 multi-object fibers or 20 mini-IFUs (mIFUs) for each observation, or a single wide-field IFU (the large IFU, LIFU). The fibers are fed into a dual-beam spectrometer located in an enclosure on the telescope’s Nasmyth platform. The spectrometer measures nearly 1000 spectra simultaneously at a spectral resolution of R~5000 over an instantaneous wavelength range of 366–959 nm. In high-resolution mode this is R~20,000 over two more-limited wavelength regions.

When WEAVE is complete in late 2017, it will be the most capable (in terms of field size x number of fibers x resolution x wavelength coverage x system efficiency) wide-field multi-object spectrometer on any telescope and the only massively-multiplexed high-resolution spectrometer in the northern hemisphere. WEAVE is the instrument required for full scientific exploitation of the Gaia, LOFAR, and APERTIF surveys in the Northern Hemisphere, as recommended by the ASTRONET Roadmap. WEAVE will also be used to study the evolution of stars, the co-evolution of galaxies and their environments, and the structure of the Universe.

WEAVE is a collaboration between the UK (STFC RAL Space and Oxford, Liverpool John Moores, and Cambridge University), NOVA, Spain (IAC), the Isaac Newton Group of Telescopes, France (GEPI), Italy (INAF), Hungary (Konkoly Observatory), and Mexico (INAOE). RAL Space/Oxford University jointly has the PI role, and NOVA holds the Deputy PI role. NOVA is responsible for the WEAVE spectrometer system. This includes management, design, manufacturing, assembly, integration, testing and commissioning. Mechanical design, mechanisms, mechanics, and optics are provided by NOVA. The detector and cryostat subsystem is provided by Liverpool John Moores University (UK), and the VPH grating subsystem is provided by INAF. Optical design for the spectrograph system is provided by RAL (UK), optical procurement and alignment is handled by NOVA, and polishing and coating is done by INAOE (Mexico), as in-kind contribution to the project, with some pieces polished by TNO (NL). Instrument control is provided by the IAC (Spain), Padova (INAF), and the ING. Responsibility for this system is held by NOVA’s Optical-IR instrumentation group. NOVA is also responsible for design of the LIFU and mIFU subsystems of the WEAVE fiber system, including management, optical design (for both IFU subsystems) and mechanical designs (for the LIFU subsystem only), as well as manufacturing, assembly, integration, and testing (MAIT) of the LIFU subsystem. The Netherlands is also responsible for the development of the science case and survey planning.

For detailed information on WEAVE, please refer to the project website.

The NOVA principal investigator for WEAVE is Prof. dr. Scott Trager (Kapteyn institute, Groningen).