Imaging spectroscopy is intended to be coupled with adaptive optics (AO) on large telescopes, such as EST, in order to produce high spatial and temporal resolution measurements of velocities and magnetic fields upon a 2D FOV. We propose a Multichannel Subtractive Double Pass (MSDP) incorporated to the EST visible and IR spectrographs, using new generation slicers (56 channels, high spectral resolution) which will benefit of AO and polarimeters. The aim is to produce 56-channel spectra images with the spatial resolution of the AO and reconstitute cubes of instantaneous data (X, Y, lambda) at high cadence, allowing the study of the plasma dynamics and magnetic fields. The MSDP is compatible with most polarimetric methods (we shall discuss only two of them).

The Meudon Solar Tower (MST) is a 0.60 m telescope dedicated to spectroscopic observations of solar regions. It includes a 14-meter focal length spectrograph which offers high spectral resolution. The spectrograph works either in classical thin slit mode (R > 300000) or 2D imaging spectroscopy (60000 < R < 180000). This specific mode is able to provide high temporal resolution measurements (1 min) of velocities and magnetic fields upon a 2D field of view, using the Multichannel Subtractive Double Pass (MSDP) system. The purpose of this paper is to describe the capabilities of the MSDP at MST with available slicers for broad and thin lines. The goal is to produce multichannel spectra-images, from which cubes of instantaneous data (x, y, $\lambda$) are derived, in order to study of the plasma dynamics and magnetic fields (with polarimetry).

Investigations of the dynamics of the hot coronal plasma are crucial for understanding various space weather phenomena and making in-depth analyzes of the global heating of the solar corona. We present here numerical simulations of observations of siphon flows along loops (simple semi-circular flux ropes) to demonstrate the capabilities of the Solar Line Emission Dopplerometer (SLED), a new instrument under construction for imaging spectroscopy. It is based on the Multi-channel Subtractive Double Pass (MSDP) technique, which combines the advantages of filters and slit spectrographs. SLED will observe coronal structures in the forbidden lines of FeX 637.4 nm and FeXIV 530.3 nm, and will measure Doppler shifts up to 150 km/s at high precision (50 m/s) and cadence (1 Hz). It is optimized for studies of the dynamics of fast evolving events such as flares or Coronal Mass Ejections (CMEs), as well as for the detection of high-frequency waves. Observations will be performed with the coronagraph at Lomnicky Stit Observatory (LSO), and will also occur during total solar eclipses as SLED is a portable instrument.

Observations of the dynamics of solar coronal structures are necessary to investigate space weather phenomena and global heating of the corona. The profiles of high temperature lines emitted by the hot plasma are usually integrated by narrow band filters or recorded by classical spectroscopy. We present in this paper details of a new transportable instrument (under construction) for imaging spectroscopy: the Solar Line Emission Dopplerometer (SLED). It uses the Multi-channel Subtractive Double Pass (MSDP) technique, which combines the advantages of both filters and narrow slit spectrographs, i.e. high temporal, spatial and spectral resolutions. The SLED will measure at high cadence (1 Hz) the line-of-sight velocities (Doppler shifts) of hot coronal loops, in the forbidden lines of FeX 6374 Å and FeXIV 5303 Å. It will follow the dynamics of fast evolving events of solar activity such as flares or Coronal Mass Ejections (CMEs), and also study coronal heating by short period waves. Observations will be performed with the coronagraph at the Lomnický Štít Observatory (LSO, in Slovakia) or during total eclipses. The SLED will also observe the dynamics of solar prominences in Hα 6563 Å or He D3 5876 Å lines when mounted on the Białków coronagraph (near Wrocław, Poland). It is fully compatible with polarimetric measurements by various techniques.

WEAVE is a new wide-field spectroscopy facility proposed for the prime focus of the 4.2m William Herschel Telescope. The facility comprises a new 2-degree field of view prime focus corrector with a 1000-multiplex fibre positioner, a small number of individually deployable integral field units, and a large single integral field unit. The IFUs (Integral Field Units) and the MOS (Multi Object Spectrograph) fibres can be used to feed a dual-beam spectrograph that will provide full coverage of the majority of the visible spectrum in a single exposure at a spectral resolution of similar to 5000 or modest wavelength coverage in both arms at a resolution similar to 20000. The instrument is expected to be on-sky by the first quarter of 2018 to provide spectroscopic sampling of the fainter end of the Gaia astrometric catalogue, chemical labeling of stars to V similar to 17, and dedicated follow up of substantial numbers of sources from the medium deep LOFAR surveys.After a brief description of the Fibre System, we describe the fibre test bench, its calibration, and some test results. We have to verify 1920 fibres from the MOS bundles and 740 fibres from the mini-IFU bundles with the test bench. In particular, we present the Focal Ratio Degradation of a cable.

We present an overview of and status report on the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT). WEAVE principally targets optical ground-based follow up of upcoming 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 spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, 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 final design and early procurement phase, with commissioning at the telescope expected in 2017.

The Observatoire de Paris is constructing a prototype Small-Sized Telescope (SST) for the Cherenkov Telescope Array (CTA), named SST-GATE, based on the dual-mirror Schwarzschild-Couder optical design. Considering the mirrors size and its specific curvature and the optical requirements for the Cherenkov imaging telescope, a non-conventional process has been used for designing and manufacturing the mirrors of the SST-GATE prototype. Based on machining, polishing and coating of aluminium bulk samples, this process has been validated by simulation and tests that will be detailed in this paper after a discussion on the Schwarzschild-Couder optical design which so far has never been used to design ground based telescopes.Even if the SST-GATE is a prototype for small size telescopes of the CTA array, the primary mirror of the telescope is 4 meters diameter, and it has to be segmented. Due to the dual-mirror configuration, the alignment is a complex task that needs a well defined and precise process that will be discussed in this paper.

WEAVE is the next-generation wide-field optical spectroscopy facility for the William Herschel Telescope (WHT) in La Palma, Canary Islands, Spain. WEAVE mainly aims at spectroscopic follow-up of ground-based (e.g. LOFAR) and space-based (GAIA) surveys. The facility consists of a new 2-degree field-of-view prime focus corrector with a 1000- multiplex fibre positioner, a small number of individually deployable integral field units, and a large single integral field unit. The IFUs (Integral Field Units) and the MOS fibres can be used to feed a dual-beam spectrograph that will provide full coverage of the majority of the visible spectrum in a single exposure at a spectral resolution of ~5000 or modest wavelength coverage in both arms at a resolution ~20000. The instrument is expected to be on-sky by 2017 to provide spectroscopic sampling of the fainter end of the Gaia astrometric catalogue, chemical labeling of stars to V~17, and dedicated follow up of substantial numbers of sources from the medium deep LOFAR surveys. After a brief description of the MOS fibre bundle, we described the proposed test plan and the test bench of the 2x1000 WEAVE MOS fibres. The test bench allows us to evaluate the Focal Ratio Degradation and the throughput of the fibers fitted with their buttons and slitlets.

For the future European Solar Telescope (EST) the Observatoire de Paris proposes a new generation of MSDP: an imaging spectro-polarimetry instrument. To validate this new generation, we develop a beam slicer prototype that will be tested and validated on an optical bench and on existing telescopes.The prototype called S4I (Spectral Sampling with Slicer for Solar Instrumentation) is under construction and tested at the Observatoire de Paris. It validates the opto-mechanical feasibility of the new beam slicer. The manufacture is now complete: we give a description of the whole system. We give also some results of the first tests.

A large fraction of the present-day stellar mass was formed between z = 0.5 and z ~ 3 and our understanding of the formation mechanisms at work at these epochs requires both high spatial and high spectral resolution: one shall simultaneously obtain images of objects with typical sizes as small as 1–2 kpc (~ 0″.1), while achieving 20–50 km/s (R≥ 5000) spectral resolution. In addition, the redshift range to be considered implies that most important spectral features are redshifted in the near-infrared. The obvious instrumental solution to adopt in order to tackle the science goal is therefore a combination of multi-object 3D spectrograph with multi-conjugate adaptive optics in large fields. A very promising way to achieve such a technically challenging goal is to relax the conditions of the traditional full adaptive optics correction. A partial, but still competitive correction shall be prefered, over a much wider field of view. This can be done by estimating the turbulent volume from sets of natural guide stars, by optimizing the correction to several and discrete small areas of few arcsec 2 selected in a large field (Nasmyth field of 25 arcmin) and by correcting up to the 6th, and eventually, up to the 60th Zernike modes. Simulations on real extragalactic fields, show that for most sources (> 80%), the recovered resolution could reach 0″. 15–0″.25 in the J and H bands. Detection of point-like objects is improved by factors from 3 to ≥10, when compared with an instrument without adaptive correction. The proposed instrument concept, FALCON, is equipped with deployable mini-integral field units (IFUs), achieving spectral resolutions between R=5000 and 20000. Its multiplex capability, combined with high spatial and spectral resolution characteristics, is a natural ground based complement to the next generation of space telescopes. Galaxy formation in the early Universe is certainly a main science driver. We describe here how FALCON shall allow to answer puzzling questions in this area, although the science cases naturally accessible to the instrument concept makes it of interest for most areas of astrophysics.