Nicolas A. Sosa

LIRIS: a long-slit intermediate-resolution infrared spectrograph for the WHT

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.

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.

LIRIS (long-slit intermediate-resolution infrared spectrograph): project status

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.

LIRIS (Long-slit Intermediate Resolution Infrared Spectrograph): Assembly Integration and verification

LIRIS is a near-infrared (0.9 - 2.4 microns) intermediate resolution spectrograph (R = 1000-3000) conceived as a common user instrument for the (WHT) at the Observatorio del Roque de los Muchachos (ORM) La Palma. LIRIS is now being assembled, integrated and virified at the Instituto Astrofisico de Canarias (IAC). LIRIS will have imaging, long-slit and multi-object spectroscopy working modes. Coronography and polarimetry capabilities will eventually be added. Image capability will allow easy target acquisition.

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.

Initial proposal for the ORM 8-m telescope control system design

The Instituto de Astrofisica de Canarias (IAC) is taking preliminary steps towards the building of an 8-m class optical-infrared telescope to be placed at the Observatorio del Roque de Los Muchachos (ORM) on the island of La Palma in the Canary Islands, Spain. This paper presents a brief description of the preliminary conceptual design of the control system for the telescope and its instrumentation in all planned modes of observation and configurations. An outline of the devices that are to be controlled and the functions that are to be performed is presented, together with a description of the system architecture. The system will be distributed and highly modular, and will allow for an easy and efficient exchange of instruments, focal stations and observing modes. It will also be designed so that technological upgrades can be implemented at low cost and minimum down-time.

Active-passive correction of wind buffeting deformation on large thin meniscus mirrors

This paper presents a solution to correct wind induced deformation on a 8.0 m thin meniscus mirror supported by a system of astatic active supports. The correction scheme is based on an active correction using the force actuators which support the mirror, and a passive rate dependent coupling of the mirror to the cell. The paper identifies the fundamental design parameters of the passive correction system and the active controller, and shows its wind attenuation capabilities. A 3D simulation verifies the good performance of the system for wind velocities of about 45 km/h. Furthermore, the influence of cell deflection on the mirror due to the passive coupling system is 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.

Multiprocessor data acquisition system for a 256x256-pixel infrared camera

The Department of Detectors of the Instituto de Astrofisica de Canarias, Spain is developing a data acquisition system (DAS) for an infrared camera based in a 256 X 256 InSb detector. The camera is going to work from 1 to 5 microns wavelength, with a scale on the sky of 0.5 arcsec per pixel, and will be installed as a common user instrument at the Carlos Sanchez Telescope in the Observatorio del Teide (Canary Island, Spain). A multiprocessor architecture has been chosen for the DAS, due to the very tight requirements on real time processing, and high speed storage capability (20 images per second readout rate, 2 images per second storage rate). The complete system is split into two main parts, the front end electronics and the user workstation. They are interconnected through an ETHERNET link.

Detector test and calibration facility at IAC

The reliable knowledge of a detector is very important in astrophysical research The aim of IAC (Instituto de Asirofisica de Canarias Spain) is to dispose of a versatile system to test evaluate and calibrate a big vanety of imaging detectors which viill be opc ned in the future to the scientific community The main features of this detector test bench are as follows (a) Wide spectral range (JR and visible) and (b) Wide radiation response range For this purpose a compact and c omplete arrangement has been designed Optical, mechanic ,cryogenic and electronic devices are flexible enough to allow the acquisition of data necessary to characterize the detector in a direct way (linearity, dark noise, spectral and time response,...). The high speed of the readout, the data acquisition system and other parameters are designed in such a way, that will make the facility virtually independent of the detector itself. This will allow reliable comparison between different detectors, and also with approved standards. Several procedures and practical examples are extensively discussed in the paper