Here is presented the tests results and the lessons learnt concerning an opto-mechanical device to scan the GREGOR telescope field of view. The scanning is done by means of a set of mirrors and a mechanism which allows to keep the optical path length constant, regardless the portion of the field being scanned. This system is intended to feed a static image slicer used for solar observations. The tight level of tolerances required makes its design and tests a real challenging activity which produces a lot of unexpected lessons to learn. The story after the issues detection, the consequent root cause analysis, the additional tests and tools developed to study the phenomena, and the construction of the solutions and issue mitigation mechanisms provides a good background to elaborate some recommendations for future developments.
We present the commissioning of an IFU based on image-slicers and a 2D-Field-of-View Scanning System (FoV-SS) for the GREGOR Infrared Spectrograph (GRIS). The prototype of the image-slicer has eight slices of 1.8 mm x 0.1 mm in Zerodur, covering an area of 20 arcsec<sup>2</sup>. The FoV-SS, equipped with three Degrees of Freedom (DoF), allows to scan a region of 1 arcmin<sup>2</sup>, feeding the image-slicer with different portions of the field of view. A batch of tests was done during the Assembly, Integration and Verification (AIV) at GREGOR telescope.
EMIR is the NIR imager and multi-object spectrograph common user instrument for the GTC and it has recently passed its first light on sky. EMIR was built by a Consortium of Spanish and French institutes led by the IAC. EMIR has finished its AIV phase at IAC facilities and it is now in commissioning on sky at GTC telescope, having completed the first run. During previous cool downs the EMIR subsystems have been integrated in the instrument progressively for verifying its functionality and performance. In order to fulfil the requirements, prepare the instrument to be in the best conditions for installation in the telescope and to solve unexpected electronics drawbacks, some changes in the implementation have been accomplished during AIV. In this paper it is described the adjustments, modifications and lessons learned related to electronics along AIV stages and the commissioning in the GTC. This includes actions in different subsystems: Hawaii2 detector and its controller electronics, Detector translation Unit, Multi object slit, wheels for filters and grisms, automatisms, vacuum, cryogenics and general electronics.
We report the results on the EMIR<sup>1</sup> (Espectrógrafo Multiobjeto Infra-Rojo) performances after the commissioning period of the instrument at the Gran Telescopio Canarias (GTC). EMIR is one of the first common user instruments for the GTC, the 10 meter telescope operating at the Roque de los Muchachos Observatory (La Palma, Canary Islands, Spain). EMIR is being built by a Consortium of Spanish and French institutes led by the Instituto de Astrofísica de Canarias (IAC). EMIR is primarily designed to be operated as a MOS in the K band, but offers a wide range of observing modes, including imaging and spectroscopy, both long slit and multiobject, in the wavelength range 0.9 to 2.5 μm. The development and fabrication of EMIR is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain). After an extensive and intensive period of system verification at the IAC, EMIR was shipped to the GTC on May 2016 for its integration at the Nasmyth platform. Once in the observatory, several tests were conducted to ensure the functionality of EMIR at the telescope, in particular that of the ECS (EMIR Control System) which has to be fully embedded into the GCS (GTC Control System) so as to become an integral part of it. During the commissioning, the main capabilities of EMIR and its combined operation with the GTC are tested and the ECS are modified to its final form. This contribution reports on the details of the EMIR operation at the GTC obtained so far, on the first commissioning period.
The European Solar Telescope (EST) is a 4-meter facility to be built in Canary Islands in the near future. Extensive daytime turbulence observation campaigns with the long baseline SHABAR instrument has been carried out in the two candidate sites from 2011 up to the end of 2014. The collected data together with nighttime turbulence data allow the site characterization and the computation of average turbulence profiles. These profiles can be used to feed numerical simulations in order to take important design decisions for the multiconjugate adaptive optics (MCAO) system in the telescope. This paper describes the main tasks developed in this context up to date.
An image slicer has been proposed for the Integral Field Spectrograph  of the 4-m European Solar Telescope (<i>EST</i>)  The image slicer for <i>EST</i> is called <i>MuSICa</i> (Multi-Slit Image slicer based on collimator-Camera)  and it is a telecentric system with diffraction limited optical quality offering the possibility to obtain high resolution Integral Field Solar Spectroscopy or Spectro-polarimetry by coupling a polarimeter after the generated slit (or slits). Considering the technical complexity of the proposed Integral Field Unit (<i>IFU</i>), a prototype has been designed for the <i>GRIS </i>spectrograph at <i>GREGOR</i> telescope at Teide Observatory (Tenerife), composed by the optical elements of the image slicer itself, a scanning system (to cover a larger field of view with sequential adjacent measurements) and an appropriate re-imaging system. All these subsystems are placed in a bench, specially designed to facilitate their alignment, integration and verification, and their easy installation in front of the spectrograph. This communication describes the opto-mechanical solution adopted to upgrade <i>GRIS</i> while ensuring repeatability between the observational modes, <i>IFU</i> and long-slit. Results from several tests which have been performed to validate the opto-mechanical prototypes are also presented.
The European Solar Telescope,<i> EST</i>, (, ) is a 4-meter solar telescope to be built in the Canary Islands in the near future. In order to select the best configuration for the EST telescope facilities, thermal and <i>CFD</i> analyses have been carried out to evaluate the seeing degradation produced by the telescope environment. The aim of this study is to calculate the values of optical parameters in different configurations and to find out which one causes the lowest image quality degradation. Starting from the determination of seeing degradation along the optical path by <i>CFD</i> techniques, several configurations have been compared making it possible to decide the future development line for the <i>EST</i>.
Integral Field Spectroscopy is an innovative technique that is being implemented in the state-of-the-art instruments of the
largest night-time telescopes, however, it is still a novelty for solar instrumentation. A new concept of image slicer,
called MuSICa (Multi-Slit Image slicer based on collimator-Camera), has been designed for the integral field
spectrograph of the 4-m European Solar Telescope. This communication presents an image slicer prototype of MuSICa
for GRIS, the spectrograph of the 1.5-m GREGOR solar telescope located at the Observatory of El Teide. MuSICa at
GRIS reorganizes a 2-D field of view of 24.5 arcsec into a slit of 0.367 arcsec width by 66.76 arcsec length distributed
horizontally. It will operate together with the TIP-II polarimeter to offer high resolution integral field spectropolarimetry.
It will also have a bidimensional field of view scanning system to cover a field of view up to 1 by 1 arcmin.