A variety of electromagnetic interference (EMI) issues can emerge during the development of an astronomical instrument impacting project scope, budget and schedule. Furthermore, if the problem is detected at the observatory it would lead to delay the commissioning of the instrument or can degrade the instrument operation performance. To reduce the interference at levels that no longer represent a problem, namely, to achieve the instrument’s electromagnetic compatibility (EMC) its developers need to tackle the problem in an integrated approach along the entire project cycle development, starting at the early stages. In this paper we dig into some reported EMI issues related to astronomical instrumentation and the proactive measures taken in some observatories to preserve EMC. We present the main practices to achieve EMC, from the electrical engineering perspective, and we identify the key aspects that the project team needs to take into account from the systems engineering and project management perspectives.
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 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.
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.
FRIDA (inFRared Imager and Dissector for the Adaptive optics system of the Gran Telescopio Canarias
(GTC)) is designed as a diffraction limited instrument that will offer broad and narrow band imaging and
integral field spectroscopy capabilities with low, intermediate and high (R ~ 30,000) 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 Teledyne 2Kx2K detector. FRIDA will be based on a
Nasmyth B of GTC, behind the adaptive optics (AO) system. The key scientific objectives of the instrument
include studies of solar system bodies, low mass objects, circumstellar outflow phenomena in advanced stages
of stellar evolution, active galactic nuclei high redshift galaxies, including resolved stellar populations, semidetached
binary systems, young stellar objects and star forming environments. FRIDA subsystems are
presently being manufactured and tested. In this paper we present the challenges to perform the verification of
some critical specifications of a cryogenic and diffraction limited NIR instrument as FRIDA. FRIDA is a
collaborative project between the main GTC partners, namely, Spain, México and Florida.
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.
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.