HARMONI is a visible and near-IR integral field spectrograph, providing the E-ELT's spectroscopic capability at first
light. It obtains simultaneous spectra of 32000 spaxels, at a range of resolving powers from R~4000 to R~20000,
covering the wavelength range from 0.47 to 2.45 μm. The 256 × 128 spaxel field of view has four different plate scales,
with the coarsest scale (40 mas) providing a 5″ × 10″ FoV, while the finest scale is a factor of 10 finer (4mas).
We describe the opto-mechanical design of HARMONI, prior to the start of preliminary design, including the main subsystems
- namely the image de-rotator, the scale-changing optics, the splitting and slicing optics, and the spectrographs.
We also present the secondary guiding system, the pupil imaging optics, the field and pupil stops, the natural guide star
wavefront sensor, and the calibration unit.
OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) was the optical Day One instrument
for the 10.4m Spanish telescope GTC. It is installed at the Observatorio del Roque de Los Muchachos (La Palma, Spain).
This instrument has been operational since March-2009 and covers from 360 to 1000 nm. OSIRIS observing modes
include direct imaging with tunable and conventional filters, long slit and low resolution spectroscopy. OSIRIS wide
field of view and high efficiency provide a powerful tool for the scientific exploitation of GTC. OSIRIS was developed
by a Consortium formed by the Instituto de Astrofísica de Canarias (IAC) and the Instituto de Astronomía de la
Universidad Nacional Autónoma de México (IA-UNAM). The latter was in charge of the optical design, the manufacture
of the camera and collaboration in the assembly, integration and verification process. The IAC was responsible for the
remaining design of the instrument and it was the project leader. The present paper considers the development of the
instrument from its design to its present situation in which is in used by the scientific community.
We present the final global design and performances of EMIR, the NIR multi-object spectrograph of the GTC, as well as the plan for its early scientific exploitation. EMIR, currently in the middle of its final phase, 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 and French 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, which include imaging and spectroscopy, both long slit and multi-object, in the wavelength range 0.9 to 2.5 mm. It is equipped with two innovative subsystems: a robotic reconfigurable multi-slit mask and dispersive elements formed by the combination of high quality diffraction grating and conventional prisms, both at the heart of the instrument. The present status of development, expected performances, schedule and plans for scientific exploitation are described and discussed. This project is mostly funded by GRANTECAN and the Plan Nacional de Astronomia y Astrofisica (National Plan for Astronomy and Astrophysics, Spain).
EMIR is the NIR multi-object imager and spectrograph for the GTC (Gran Telescopio Canarias). The instrument PDR phase was held successfully in March 2003, and we are at present in the middle of the ADR (Advanced Design Phase) during which a number of mechanical concepts will be tested on development prototypes to ensure the feasibility of the PDR proposed design. This presentation contains a technical description of the mechanical design of the instrument, as well as the prototypes development. The mechanical design is essentially built around the optical layout by providing an optical bench for mounting the optomechanics, the mechanisms and the detector, all this inside a custom-designed vacuum vessel and with the corresponding cooling system. One of its main design features is the use of a cryogenic reconfigurable slit mechanism to generate a multi-slit configuration, a long slit or an imaging aperture at the telescope focal plane. This feature will permit to maintain the instrument in operation conditions for a long time and take advantages in both a classically scheduled and a queued service observing schemes
This paper shows the different design concepts and techniques employed in the structural and thermal analysis of EMIR (Espectrografo Multiobjeto Infrarrojo), nowadays under development at the Instituto de Astrofisica de Canarias.
A Camera Barrel, located in the OSIRIS imager/spectrograph for the Gran Telescopio Canarias (GTC), is described in this article. The barrel design has been developed by the Institute for Astronomy of the University of Mexico (IA-UNAM), in collaboration with the Institute for Astrophysics of Canarias (IAC), Spain. The barrel is being manufactured by the Engineering Center for Industrial Development (CIDESI) at Queretaro, Mexico. The Camera Barrel includes a set of eight lenses (three doublets and two singlets), with their respective supports and cells, as well as two subsystems: the Focusing Unit, which is a mechanism that modifies the first doublet relative position; and the Passive Displacement Unit (PDU), which uses the third doublet as thermal compensator to maintain the camera focal length and image quality when the ambient temperature changes. This article includes a brief description of the scientific instrument; describes the design criteria related with performance justification; and summarizes the specifications related with misalignment errors and generated stresses. The Camera Barrel components are described and analytical calculations, FEA simulations and error budgets are also included.
EMIR is a NIR multiobject spectrograph with imaging capabilities to be used at the GTC. A general description of instrument performances, as well as the updated optical and mechanical layouts, can be found elsewhere on these proceedings (reference documents 4, 6 and 7). After the successful results of the Preliminary Design Review in March 2003, EMIR optical design is now complete. Some specific features of the optical components make it particularly difficult to mount them in the instrument. For example, the first collimator lens in EMIR is one of the largest Fused Silica lenses ever mounted to work under cryogenic conditions, and some other lenses in the system present features such as aspheric surfaces, tight centering tolerances etc. The analysis of the testing being done in order to validate three different lens mounting design concepts is presented here, as well as the detailed status of the lens mounting design solutions adopted.
Tight stability requirements for the imager/spectrograph OSIRIS (a Day One optical instrument for the GTC telescope) demand a careful treatment of thermal effects within the OSIRIS camera. Mostly due to the thermal response of refraction indices of its glasses (and not so much to curvature, spacing or thickness variations of the lenses), the camera optics alone degrades beyond requirements the image quality and plate scale under the expected ambient temperature variations (about 1.8 °C/hour). Thermal effects and thermal compensator studies of the OSIRIS camera are first summarized, before discussing how the motion (of a few microns per °C) of the 3rd camera doublet, as a sole compensator, practically eliminates thermal influences on both image quality and plate scale. A concept for the passive implementation of the compensator is also discussed.
OSIRIS (Optical System for Imaging and low/intermediate-Resolution Integrated Spectroscopy) is an instrument designed to obtain images and low resolution spectra of astronomical objects in the optical domain (from 365 through 1000nm). It will be installed on Day One in the Nasmyth focus of the 10-meter Spanish GTC Telescope, although it shall be possible to install it in the Cassegrain focus as well. It is expected to be in operation at the end of 2003.
The Slit Unit is an automated slit mask loader based in cam followers technology, being designed at the IAC for the OSIRIS Spectrograph. It provides a store with space for as many as 13 multislits mask and long slit mask for an unvignetted field of view of 8.53'x8.67', available at the same time for observing purposes. A two-degrees-of-freedom mechanism allows to select one of the masks, to remove it from the cassette and to position it in the focal plane with the required repeatability. The complete design of the mechanism is presented, including an analysis of the predicted performances and a 3-D model used to check the geometry and mass properties.
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).
OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) is the optical Day One instrument for the 10.4m Spanish telescope GTC to be installed in the Observatorio del Roque de Los Muchachos (La Palma, Spain). This instrument, operational in mid-2004, covers from 360 up to 1000 nm. OSIRIS observing modes include direct imaging with tunable and conventional filters, long slit and multiple object spectroscopy and fast spectrophotometry. The OSIRIS wide field of view, high efficiency and the new observing modes (tunable imaging and fast spectrophotometry) for 8-10m class telescopes will provide GTC with a powerful tool for their scientific exploitation. The present paper provides an updated overview of the instrument development, of some of the scientific projects that will be tackled with OSIRIS and of the general requirements driving the optical and mechanical design.
EMIR is a multiobject intermediate resolution near infrared (1.0 - 2.5 microns) spectrograph with image capabilities to be mounted on the Gran Telescopio Canarias (Observatorio del Roque de los Muchachos, La Palma, Spain). EMIR is under design by a consortium of Spanish, French and British institutions, led by the Instituto de Astrofisica de Canarias. This work has been partially funded by the GTC Project Office. The instrument will deliver images and spectra in a large FOV (6 X 6 arcmin), and because of the telescope image scale (1 arcmin equals 52 mm) and the spectral resolution required, around 4000, one of the major challenges of the instrument is the optics and optomechanics. Different approaches have been studied since the initial proposal, trying to control the risks of the instrument, while fitting the initial scientific requirements. Issues on optical concepts, material availability, temperature as well as optomechanical mounting of the instrument will be presented.
LIRIS is a near-IR intermediate resolution spectrograph with added capabilities for multi-object, imaging, coronography, and polarimetry. This instrument is now being constructed at the IAC, and upon complexion will be installed on the 4.2m William Herschel Telescope at the Observatorio del Roque de Los Muchachos. The optical system uses lenses and is based on a classical collimator/camera design. Grisms are used as the dispersion elements. The plate scale matches the median seeing at the ORM. The detector is a Hawaii 1024 X 1024 HgCdTe array operating at 60K.
EMIR is a near-IR, multi-slit camera-spectrograph under development for the 10m GTC on La Palma. It will deliver up to 45 independent R equals 3500-4000 spectra of sources over a field of view of 6 feet by 3 feet, and allow NIR imaging over a 6 foot by 6 foot FOV, with spatial sampling of 0.175 inch/pixel. The prime science goal of the instrument is to open K-band, wide field multi-object spectroscopy on 10m class telescopes. Science applications range from the study of star-forming galaxies beyond z equals 2, to observations of substellar objects and dust-enshrouded star formation regions. Main technological challenges include the large optics, the mechanical and thermal stability and the need to implement a mask exchange mechanism that does not require warming up the spectrograph. EMIR is begin developed by the Instituto de Astrofisica de Canarias, the Instituto Nacional de Tecnica Aeroespacial, the Universidad Complutense de Madrid, the Observatoire Midi-Pyrennees, and the University of Durham. Currently in its Preliminary Design phase, EMIR is expected to start science operation in 2004.
We report here the main characteristics of a near IR camera devoted to astrophysical solar research, which has been developed by the Instituto de Astrofisica de Canarias (IAC). The system is now being used for photometric and spectroscopic applications, and it will also be used for spectropolarimetry in the near future. The first application is described below in detail. The IACs IR camera is based on a Rockwell 256 X 256 HgCdTe NICMOS3 array, sensitive from 1 to 2.5 microns. The necessary cooling system is a LN2- cryostat, designed and built by IR labs under out requirements. The main electronics are the standard VME- based, FPGA programmable MCE-3 system, also developed by IR labs. We have implemented different readout schemes to improve sped, reduce noise and avoid seeing effects, taking into account each specific application. Data are transferred via fiber optics to a control unit, which re-send them to the main data acquisition system. Several acquisition modes to select the best images have been implemented, and a real- time data processing is available, the entire camera has been characterized and calibrated, and the main radiometric parameters given. Preliminary test in spectroscopic observations have been made in the German Towers at the Observatorio del Teide in Tenerife, Spain, and a series of photometric measurements performed in the Swedish Solar Telescope, at the Observatorio del Roque de los Muchachos in La Palma, Spain. As examples, some scientific results are also presented.
ABEL is currently at the beginning of the design phase at the Instituto de Astrofisica de Canaris. The instrument will be equipped with the 256 X 256 Santa Barbara Research Corporation InSb FPA which will provide a working spectral range from 1 to 5 microns. For image mode three different platescales are envisaged: 0.2 inch/pixel, to be used in the thermal IR to avoid detector saturation; 0.4 inch/pixel, which will allow for sufficient sampling of the median seeing limited images below 2.5 microns; and 1.0 inch/pixel, which will be the standard in spectroscopic operations and during wide field imaging. For spectroscopy, a standard moderate spectral resolution of about 400 will be available in the JHKLM windows, which will be all fully covered in a single exposure. Additional higher spectral resolution is under consideration, which at least double. ABEL will offer a wide variety of slit widths and shapes, ranging from 1 inch to 3 inches, and including dog-leg shape. The thermal design is based on a two stages closed cycle cooler, the first stage being used for the passive optics while the second will cool directly the detector to about 30 to 40 K. The instrument is planned for the late 99 and a major cooperation with the Osservatorio de Arcetri is underway. ABEL will be installed in the f/13.8 Cassegrain focus of the 1.5m Telescopio Carlos Sanchez, at the Spanish Observatorio de El Teide, in the canarian island of Tenerife.
The Instituto de Astrofisica de Canarias (IAC) is undertaking the design and construction of a common-user near IR spectrograph (LIRIS) for the Cassegrain focus of the 4.2 m William Herschel Telescope sited at the Observatorio del Roque de Los Muchachos. LIRIS will be a near IR intermediate-resolution spectrograph designed to operate over a spectral resolution range between 1000 and 5000, with added capabilities for coronographic, multiproject and polarimetric observations. The instrument allows the combination of an adequate spatial resolution with a large useful field of view across the slit, thanks to the use of the new 1024 X 1024 pixel HgCdTe Hawaii detector manufactured by Rockwell. All the optics and mechanisms situated inside the cryostat will be cooled to below 100 K. The detector will operate at 77 K. Calibration and tracking will be made with the existing Cassegrain A and G Box, into which a near IR calibration system will be incorporated.
INTEGRAL is an optical fiber unit for performing 2D spectroscopy of extended objects at the 4.2 m. William Herschel Telescope (WHT). It is mounted at the GHRIL Nasmyth focus together with newly built acquisition, guiding, and calibration units. It makes use of the specially designed fiber spectrograph WYFFOS. This system allows up to six bundles to be mounted simultaneously. It currently contains three science oriented fiber bundles, any one of which can be easily and quickly placed in the telescope beam. Their spatial resolution elements (fiber core diameters) are 0'.45, 0'.9, and 2'.7, respectively. Hence, depending on the prevailing seeing conditions the instrument can be easily optimized for the scientific program. INTEGRAL was successfully commissioned at the WHT during a six night period in July 1997. Here we will discuss its main characteristics.
We have just finished the first tests at the telescope of an infrared camera designed and developed at the Instituto de Astrofisica de Canarias (IAC). This camera, based on a 256 X 256 focal plane array, has been built to operate at the 1.5 m Carlos Sanchez IR telescope (CST) in the Observatorio del Teide (Canary Islands, Spain). In this paper we describe the final configuration and performance of the camera. Some images taken during two telescope commissioning periods are shown.
The technology division of the Instituto de Astrofisica de Canarias (IAC) is developing a data acquisition system (DAS) for an IR camera to be used at the 1.5m Carlos Sanchez Telescope (TCS) in the Observatorio del Teide (Canary Islands, Spain). This camera will work between a wavelength of 1 and 5 microns and will employ an InSb focal plane array (FPA). The DAS and the user interface are based on a UNIX workstation with a modular transputer based controller. The IGA-256 (Cincinnati Electronics) has been evaluated as a candidate for the focal plane array. The main features related to the potential astronomical performance, such as well depth and dark current are reported. The testing procedures and present status of the camera are discussed.
The Instituto de Astrofisica de Canarias infrared camera is intended as a common user instrument for the Cassegrain focus of the Carlos Sanchez Telescope at the Observatorio del Teide. The camera will be equipped with a 256 X 256 InSb array, two filter wheels and a centered diamond turned aluminum optical system working at liquid nitrogen (LN2) temperature. This paper presents the mechanical design, tolerancing and development of the mirrors system, as well as the fabrication and testing of the optical elements.
The Instituto de Astrofisica de Canarias (IAC) is undertaking the construction of an IR camera for astronomical use at the 1.5 meter (f/13,8) Carlos Sanchez IR Telescope (CST), sited at the Observatorio del Teide (Tenerife). The camera will employ a 256 X 256 InSb focal plane array, and will be used in the 1 - 5 micron atmospheric windows. The Camera uses an optical reimaging system which maps 0.5 square arcseconds of sky per pixel. The optical system will be diamond turned in aluminum and mounted in such a way that the optical alignment is facilitated. Two filter wheels will accommodate 14 broad and narrow band filters. A SUN SPARCstation will control the camera and allow data handling and displaying of the images. With this configuration we expect to achieve sensitivities of 17 and 12.5 magnitude (3 (sigma) in 10 sec) at the K and L band respectively.
An infrared liquid nitrogen (LN2) cooled focal reducer camera has been designed to be used at the 1.5 m (f/13.8) Carlos Sanchez IR Telescope (CST) at the Observatorio del Teide. The image quality is better than 30 micrometers (typical pixel size of the detector) with an image scale of 0.5 arcsec/pixel. The final design is a very compact system which consists of a centered reflective system with a CaF2 lens which will be used as window of the dewar. The system is free of chromatic aberration, reduces the amount of coma presents in the telescope and allows us to get a homogeneous image quality over the detector. Vignetting effects on the transmission are studied and found below the 20%. The use of aluminum diamond turned optics lets us obtain the tight tolerances needed to get the maximum optical performance with a system which is practically insensitive to temperature changes. Spot diagrams at different wavelength from 1 to 5 micrometers using a real simulation of the complete system (CST + camera) are presented. The baffling of the system is also analyzed.14