J. J. Díaz

EMIR: the GTC NIR multi-object imager-spectrograph

In this contribution we review the overall features of EMIR, the NIR multiobject spectrograph of the GTC. EMIR is at present in the middle of the PD phase and will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish, French and British institutes led by the IAC. EMIR is designed to realize one of the central goals of 10m class telescopes, allowing observers to obtain spectra for large numbers of faint sources in an time-efficient manner. 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 present status of development, expected performances and schedule are described and discussed. This project is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain).

Zero Noise Wavefront Sensor Development within the Opticon European Network

This activity, funded by ESO and the European Commission through the Opticon Network will attempt to define, fabricate and fully characterize the best possible detector working at visible wavelengths suitable for wavefront sensors in Adaptive Optics (AO) systems. The detector will be a split frame transfer array built by e2v technologies and called CCD220. The frame rate will be very fast (up to 1.2 kHz) while the readout noise will be kept extremely low (typically below 1 e - ). The goal of this paper is to justify the choice of detector: an EMCCD with 240×240 pixels and 8 outputs that will provide sub- electron readout noise at 1-1.2 kHz frame rate. This paper shows that, despite the fact that EMCDDs have an excess noise factor of 1.4 due to the charge multiplication process; their virtually zero read noise should allow them to outperform the classical CCD. Such detectors do not yet exist and must be developed. Moreover, this paper explains how the OPTICON European network is organized.

A Dedicated L3Vision CCD for Adaptive Optics Applications

ESO and JRA2 OPTICON have funded the development of a compact packaged Peltier cooled 24 µm square 240×240 pixel split frame transfer 8-output back illuminated L3Vision CCD, L3CCD, by e2v technologies. The device will achieve sub-electron (goal 0.1e - ) read noise at frame rates from 25 Hz to 1.5 kHz and low dark current of 0.01 e - /pixel/frame. The development has many unique features. To obtain high frame rates, multi-output EMCCD gain registers and metal buttressing of parallel clocks will be used. To minimize risk, the baseline device will be built in standard silicon. In addition, a split wafer run will enable two speculative variants to be built; deep depletion silicon devices to improve red response and devices with an electronic shutter to extend use to Rayleigh Laser Guide Star (RLGS) applications. These are all unprecedented advancements for L3CCDs. This paper will describe requirements and outline the design established after careful consideration of the application, detector architecture, compact Peltier package, technology trade-offs, schedule and proposed test plan.

The plenoptic camera as a wavefront sensor for the European Solar Telescope (EST)

The plenoptic wavefront sensor combines measurements at pupil and image planes in order to obtain wavefront information from different points of view simultaneously, being capable to sample the volume above the telescope to extract the tomographic information of the atmospheric turbulence. After describing the working principle, a laboratory setup has been used for the verification of the capability of measuring the pupil plane wavefront. A comparative discussion with respect to other wavefront sensors is also included.

FRIDA: integral-field spectrograph and imager for the adaptive optics system of the Gran Telescopio Canarias

FRIDA (inFRared Imager and Dissector for the Adaptive optics system of the Gran Telescopio Canarias) has been designed as a diffraction limited instrument that will offer broad and narrow band imaging and integral field spectroscopy (IFS) capabilities with low, intermediate and high spectral resolutions to operate in the wavelength range 0.9 - 2.5 μm. The integral field unit is based on a monolithic image slicer and the imaging and IFS observing modes will use the same Rockwell 2Kx2K detector. FRIDA will be based at a Nasmyth focus of GTC, behind the AO system. The main design characteristics of FRIDA are described in this contribution. FRIDA is a collaborative project between the main GTC partners, namely, Spain, Mexico and Florida, lead by UNAM.

A high-resolution spectrograph for the solar telescope GREGOR

This communication shows the design, layout, mounting and start-up of a high-resolution grating spectrograph for VIS-NIR at GREGOR 1.5m Solar Telescope (Observatorio del Teide, Tenerife, Canary Islands). The instrument will be used together with the Tenerife Infrared Polarimeter (TIP-II). As special characteristics of the design, the following can be mentioned: The first folding mirror of the spectrograph can be placed in two positions to take into account the change of the optical axis introduced by the polarizing beamsplitter of TIP-II. This way the instrument is optimally aligned when used in situations with and without polarimeter. The second and third mirrors rotate the image of the entrance slit, making it parallel to the grating grooves. A system of prisms are used to adequately fit onto the detector the two orthogonal polarized beams generated by the polarimeter. Two output beams are possible, to make feasible simultaneous visible and near-infrared observations.

Electronics and mechanisms control system for FRIDA (inFRared Imager and Dissector for Adaptive optics)

FRIDA will be a common-user near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. Primary observing modes driven the instrument design are two: direct imaging and integral field spectroscopy. FRIDA will be installed at the Nasmyth-B platform of the Gran Telescopio Canarias (GTC) behind the GTC Adaptive Optics (GTCAO) system. Instrument will use diffraction-limited optics to avoid degrading the high Strehl ratios derived by the GTCAO system in the near infrared. High-performance astronomical instruments with a high reconfiguration degree as FRIDA, not only depends on optical and mechanical efficient designs but also on the good quality of its electronics and control systems design. In fact, astronomical instruments operating performance on telescope greatly relies on electronics and control system. This paper describes the main design topics for the FRIDA electronics and mechanisms control system, pointing on the development that these areas have reached on the project status. FRIDA Critical Design Review (CDR) was held on September 2011.

The participation of the Instituto de Astrofísica de Canarias in the European Solar Telescope

This communication reviews the participation of the Instituto de Astrofísica de Canarias (IAC) in the design of the European Solar Telescope. Apart of being the coordinator institution of the whole project, and, as such, responsible for the project managing, the IAC leads several tasks like overall instrument definition or characterization of the atmospheric turbulence profile with height or the definition of adequate detectors. More in particular, the IAC will design and build two long-base SHABAR (SHAdow BAnd Ranger), instruments to measure medium-altitude seeing. The IAC is also responsible for the design, together with other institutions, of the design of grating spectropolarimeters suitable for multiwavelength high spatial and spectral resolution.

EMIR: THE GTC NIR MULTI-OBJECT IMAGER-SPECTROGRAPH

no nal global y el desempe~ de EMIR, el espectr ografo para objetos m ultiples del NIR del GTC, como tambi en el plan para su aplicaci on cient ca inicial. EMIR, actualmente en sus fases nales, ser a uno de los primeros instrumentos para usuarios del GTC, el telescopio de 10 metros en construcci on por GRANTECAN en el Observatorio del Roque de los Muchachos (Islas Canarias, Espa~ A EMIR lo construye un consorcio de institutos espa~ y franceses conducido por IAC. EMIR est a dise~ para llevar a cabo uno de los objetivos centrales de los telescopios de la clase de 10 metros, lo que permitir a a los observadores obtener espectros de gran n umero de objetos d ebiles de una manera ecien te en cuanto al tiempo. EMIR est a dise~ para ser operado primariamente como un MOS en la banda K, pero ofrece adem as un amplio rango de modos observacionales, incluido imagen y espectroscop a, tanto de rendija larga como de objetos m ultiples, en el rango de longitudes de onda de 0.9 a 2.5 m. Se encuentra equipado con dos subsistemas novedosos: una m ascara de rendijas m ultiples rob otica recongurable y elementos dispersivos formados por una combinaci on de rejilla de difracci on y prismas convencionales de alta calidad, ambos localizados en el coraz on del instrumento. Se describe y discute el estado actual de desarrollo, el desempe~ esperado, el calendario y los planes de aplicaci on cient ca. Este proyecto est a nanciado mayormente por GRANTECAN y el Plan Nacional de Astronom a y Astrof sica de Espa~ na.

Thermal modeling of cooled instrument: from the WIRCam IR camera to CCD Peltier cooled compact packages

In the past decade, new thermal modelling tools have been offered to system designers. These modelling tools have rarely been used for the cooled instruments in ground-based astronomy. In addition to an overwhelming increase of PC computer capabilities, these tools are now mature enough to drive the design of complex astronomical instruments that are cooled. This is the case for WIRCam, the new wide-field infrared camera installed on the CFHT in Hawaii on the Mauna Kea summit. This camera uses four 2K×2K Rockwell Hawaii-2RG infrared detectors and includes 2 optical barrels and 2 filter wheels. This camera is mounted at the prime focus of the 3.6m CFHT telescope. The mass to be cooled is close to 100 kg. The camera uses a Gifford Mac-Mahon closed-cycle cryo-cooler. The capabilities of the I-deas thermal module (TMG) is demonstrated for our particular application: predicted performances are presented and compared to real measurements after integration on the telescope in December 2004. In addition, we present thermal modelling of small Peltier cooled CCD packages, including the thermal model of the CCD220 Peltier package (fabricated by e2v technologies) and cold head. ESO and the OPTICON European network have funded e2v technologies to develop a compact packaged Peltier-cooled 8-output back illuminated L3Vision CCD. The device will achieve sub-electron read-noise at frame rates up to 1.5 kHz. The development, fully dedicated to the latest generation of adaptive optics wavefront sensors, has many unique features. Among them, the ultra-compactness offered by a Peltier package integrated in a small cold head including the detector drive electronics, is a way to achieve amazing performances for adaptive optics systems. All these models were carried out using a normal PC laptop.