C. Keiman

Optical design of FRIDA, the integral-field spectrograph and imager for the AO 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 based on the University of Florida FISICA. Both, the imaging mode and IFS observing modes will use the same Rockwell 2K×2K detector. FRIDA will be based at a Nasmyth focus of GTC, behind the GTCAO system. The FRIDA optical design, stray light analysis, tolerance analysis and manufacturing feasibility are described in this contribution.

FRIDA, the diffraction limited NIR imager and IFS for the Gran Telescopio Canarias: status report

FRIDA is a diffraction limited imager and integral field spectrometer that is being built for the Gran Telescopio Canarias. FRIDA has been designed and is being built as a collaborative project between institutions from México, Spain and the USA. In imaging mode FRIDA will provide scales of 0.010, 0.020 and 0.040 arcsec/pixel and in IFS mode spectral resolutions R ~ 1000, 4,500 and 30,000. FRIDA is starting systems integration and is scheduled to complete fully integrated system tests at the laboratory by the end of 2015 and be delivered to GTC shortly after. In this contribution we present a summary of its design, fabrication, current status and potential scientific applications.

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.

FRIDA´s mechanisms control system structure and tests

FRIDA will be a near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. FRIDA will work in two observing modes: direct imaging and integral field spectroscopy. This paper presents the main structure of the FRIDA mechanisms control system. In order to comply with a high level of re-configurability FRIDA will comprise eight cryogenic mechanisms and one room temperature mechanism. Most of these mechanisms require high positioning repeatability to ensure FRIDA fulfills with high astronomical specifications. In order to set up the mechanisms positioning control parameters a set of programs have been developed to perform several tests of mechanisms in both room and cryogenic environments. The embedded control software for most of the FRIDA mechanisms has been developed. A description of some mechanisms tests and the software used for this purpose are presented.

Cryogenic application of an autocentering mount working at the diffraction limit

Abstract. We present the design concept and validation of a cryogenic lens mount for a noncemented doublet for the near-infrared diffraction limited instrument FRIDA. The design uses an autocentering mount that maintains the relative alignment of the lenses, acting against any displacement that may be induced by external forces by automatically returning the lenses to their nominal positions. Autocentering techniques have been used for instruments at room temperature with relatively relaxed image quality requirements. We present in detail its application to a mount for a cryogenic instrument working at the diffraction limit. The design has been tested on the collimator of FRIDA, a noncemented doublet of CaF2 and S-FTM16. We describe the alignment requirements of the system, and we show the calculations that ensure that the lenses will suffer both appropriate stresses and temperature differences. We present the experimental validation of a prototype, demonstrating that the design delivers an excellent performance without inducing unnecessary stresses on the optical components, provided that the lenses are previously aligned with very high precision.

FRIDA: diffraction-limited imaging and integral-field spectroscopy for the GTC

FRIDA is a diffraction-limited imager and integral-field spectrometer that is being built for the adaptive-optics focus of the Gran Telescopio Canarias. In imaging mode FRIDA will provide scales of 0.010, 0.020 and 0.040 arcsec/pixel and in IFS mode spectral resolutions of 1500, 4000 and 30,000. FRIDA is starting systems integration and is scheduled to complete fully integrated system tests at the laboratory by the end of 2017 and to be delivered to GTC shortly thereafter. In this contribution we present a summary of its design, fabrication, current status and potential scientific applications.

Advances in the development of FRIDA's mechanisms control system and house-keeping

FRIDA will be a near infrared imager and integral field spectrograph covering the wavelength range from 0.9 to 2.5 microns. Primary observing modes are: direct imaging and integral field spectroscopy. This paper describes the main advances in the development of the electronics and control system for both the mechanisms and house-keeping of FRIDA. In order to perform several tests of mechanisms in both room and cryogenic environments, a set of programs had been developed. All variables of the vacuum control system were determined and the main control structure based on one Programmable Logic Controller (PLC) had been established. A key function of the FRIDA’s control system is keeping the integrity of cryostat during all processes, so we have designed a redundant heating control system which will be in charge of avoiding cryostat inner overheating. In addition, some improvements of cryogenic and room temperature cabling structure are described.