Jose J. Diaz-Garcia

Characterization of OCam and CCD220, the fastest and most sensitive camera to date for AO wavefront sensing

For the first time, sub-electron read noise has been achieved with a camera suitable for astronomical wavefront-sensing (WFS) applications. The OCam system has demonstrated this performance at 1300 Hz frame rate and with 240×240-pixel frame rate. ESO and JRA2 OPTICON2 have jointly funded e2v technologies to develop a custom CCD for Adaptive Optics (AO) wavefront sensing applications. The device, called CCD220, is a compact Peltier-cooled 240×240 pixel frame-transfer 8-output back-illuminated sensor using the EMCCD technology. This paper demonstrates sub-electron read noise at frame rates from 25 Hz to 1300 Hz and dark current lower than 0.01 e-/pixel/frame. It reports on the comprehensive, quantitative performance characterization of OCam and the CCD220 such as readout noise, dark current, multiplication gain, quantum efficiency, charge transfer efficiency... OCam includes a low noise preamplifier stage, a digital board to generate the clocks and a microcontroller. The data acquisition system includes a user friendly timer file editor to generate any type of clocking scheme. A second version of OCam, called OCam2, was designed offering enhanced performances, a completely sealed camera package and an additional Peltier stage to facilitate operation on a telescope or environmentally rugged applications. OCam2 offers two types of built-in data link to the Real Time Computer: the CameraLink industry standard interface and various fiber link options like the sFPDP interface. OCam2 includes also a modified mechanical design to ease the integration of microlens arrays for use of this camera in all types of wavefront sensing AO system. The front cover of OCam2 can be customized to include a microlens exchange mechanism.

EMIR, cryogenic NIR multi-object spectrograph for GTC

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.

The EMIR optical system

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.

Electronic testing of the IAC infrared camera

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 control unit of the near infrared spectrograph of the EUCLID space mission: preliminary design

The Near Infrared Spectrograph and Photometer (NISP) is one of the instruments on board the ESA EUCLID mission. The Universidad Politecnica de Cartagena and Instituto de Astrofisica de Canarias are responsible of the Instrument Control Unit of the NISP (NI-ICU) in the Euclid Consortium. The NI-ICU main functions are: communication with the S/C and the Data Processing Unit, control of the Filter and Grism Wheels, control of the Calibration Unit and thermal control of the instrument. This paper presents the NI-ICU status of definition and design at the end of the preliminary design phase.

Analysis of Connection Schemes between the ICU and the DPU of the NISP Instrument of the Euclid Mission

Euclid is a middle class ESA mission dedicated to the observation of the space, more in particular the dark matter and the dark energy. To do so, Euclid features two instruments: VIS (visible imager) and NISP (Near-Infrared Spectrometer and Photometer). Within the NISP, the NI-ICU (NISP Instrument Control Unit) is in charge of the control and monitoring of the instrument, and the communication with the spacecraft and the Data Processing Unit (NI-DPU). This paper summarizes the analysis carried out at the Universidad Politecnica de Cartagena (UPCT) and the Instituto de Astrofisica de Canarias (IAC) with regard to the communication link between NI-ICU and NI-DPU at the end of phase B1, 9 months before IPDR (Instrument Preliminary Design Review).

Performance of a modal zone wavefront recovery algorithm (Hudgin) implemented on FPGAs for its use in ELTs

The use of AO in Extremely Large Telescopes, used to improve performances in smaller telescopes, becomes now mandatory to achieve diffraction limited images according to the large apertures. On the other hand, the new dimensions push the specifications of the AO systems to new frontiers where the order of magnitude in terms of computation power, time response and the required numbers of actuators impose new challenges to the technology. In some aspects implementation methods used in the past result no longer applicable. This paper examines the real dimension of the problem imposed by ELTs and shows the results obtained in the laboratory for a real modal wavefront recovery algorithm (Hudgin) implemented in FPGAs. Some approximations are studied and the performances in terms of configuration parameters are compared. Also a preferred configuration will be justified.

Near-infrared camera for solar research: a photometric application

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.

First results of the Instituto de Astrofisica de Canarias infrared camera

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.

1-5-μm infrared camera of the IAC

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.