The first generation of ELT instruments includes an optical-infrared high resolution spectrograph, indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). ANDES consists of three fibre-fed spectrographs (UBV, RIZ, YJH) providing a spectral resolution of ∼100,000 with a minimum simultaneous wavelength coverage of 0.4-1.8 µm with the goal of extending it to 0.35-2.4 µm with the addition of a K band spectrograph. It operates both in seeing- and diffraction-limited conditions and the fibre-feeding allows several, interchangeable observing modes including a single conjugated adaptive optics module and a small diffraction-limited integral field unit in the NIR. Its modularity will ensure that ANDES can be placed entirely on the ELT Nasmyth platform, if enough mass and volume is available, or partly in the Coudé room. ANDES has a wide range of groundbreaking science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars, tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The ANDES project is carried forward by a large international consortium, composed of 35 Institutes from 13 countries, forming a team of more than 200 scientists and engineers which represent the majority of the scientific and technical expertise in the field among ESO member states.
NIRPS is an infrared precision Radial Velocity (pRV) spectrograph covering the range 950 nm-1800 nm. NIRPS uses a high-order Adaptive Optics (AO) system to couple the starlight into a fiber corresponding to 0.4" on the sky as efficiently or better than HARPS or ESPRESSO couple the light in a 1.0" fiber. This allows the spectrograph to be very compact, more thermally stable, and less costly. Using a custom tan(θ)=4 dispersion grating in combination with a start-of-the-art Hawaii4RG detector makes NIRPS very efficient with complete coverage of the YJH bands at just under 100 000 resolution. On the ESO 3.6-m telescope, NIRPS and HARPS are working simultaneously on the same target, building a single powerful high-resolution, high-fidelity spectrograph covering the 0.37-1.8 µm domain. NIRPS will complement HARPS in validating Earth-like planets found around G and K-type stars whose signal is at the same order of magnitude than the stellar noise. While the telescope-side AO system was installed on the ESO 3.6-m telescope in 2019, the infrared cryogenic spectrograph has been integrated at the telescope in early-2022 and has had first light in June 2022. Results from the first light mission show that NIRPS performs very nicely, that the AO system works up to magnitude I=14.5, that the transmission matches requirements and that the RV stability of 1 m/s is within reach While performance assessment is ongoing, NIRPS has demonstrated on-sky m/s-level stability over a night and <3 m/s level over two weeks. Limitations on the RV performances arise from modal noise that can be mitigated through better scrambling strategies. Better performances are also expected following a grating upgrade in July 2022; these will be tested in late-2022.
NIRPS is a near-infrared (YJH bands), fiber-fed, high-resolution precise radial velocity (PRV) spectrograph installed at the ESO 3.6-m telescope in La Silla, Chile. Using a dichroic, NIRPS will be operated simultaneously with the optical HARPS PRV spectrograph and will be used to conduct ambitious planet-search and characterization surveys. NIRPS aims at detecting and characterizing Earth-like planets in the habitable zone of low-mass dwarfs and obtain high-accuracy transit spectroscopy of exoplanets. The spectrograph is compact for better thermal stability. Using a custom R4 grating in combination with a state-of-the-art Hawaii4RG detector, the instrument provides a high resolution and high stability over the range of 950-1800 nm. This paper focuses on the lens and optomechanical design, assembly, and test of NIRPS’s spectrograph. Some performance tests conducted at Université Laval (Canada) during the integration and at La Silla during commissioning are presented
A near-IR high-resolution, R≈80000 spectrometer has been developed at IPAG to directly characterize the atmosphere of exoplanets using adaptive optics (AO) assisted telescopes, and a single-mode fiber-injection unit. A first technical test with the 200’ Hale telescope at Palomar Observatory occurred in March 2022 using the PALM3000 AO system offered by this telescope. Observations have also been made at the same time with the PARVI spectrometer so that a direct comparison can be made between the two instruments. This spectrometer uses a virtually imaged phased array (VIPA) instead of an echelle grating, resulting in a very compact optical layout that fits in a 0.25m3 cryostat. Using a quarter of an H2RG detector, the spectrometer analyses the middle part of the H-band, from 1.57 to 1.7 microns for 2 sources whose light is transferred from the telescope to the spectrometer using single-mode fibers. By design, the transmission of the spectrometer is expected to be 40-50%, which is 2-3 times higher than the transmission of current high-resolution spectrometers such as CRIRES+ and NIRSPEC. A damaged cross-disperser limited it to 21%, however. A replacement grating with a correct, twice as high efficiency has been procured after the on-sky demonstration. In addition to recalling the main specifications of the VIPA spectrometer, this paper presents the control software, the calibration process, and the reduction pipeline that have been developed for the instrument. It also presents the results of the on-sky technical test with the Hale telescope, as well as measurements of the effective resolution and transmission, along with a comparison of a spectrum of the sun obtained with the spectrometer with the BASS2000 reference spectrum. Planned modifications are also discussed. That includes the integration of a new dedicated H2RG detector, and of K-band optics.
NIRPS (Near Infra Red Planet Searcher) is a near-infrared, fiber-fed, high-resolution, high precision radial velocity (pRV) spectrograph to be installed at ESO 3.6m telescope in La Silla Observatory in Chile. High precision radial velocity measurements require to have a very stable optical assembly. The gluing of optical elements in their mounts with A12 epoxy was selected as bonding process to minimize kinematic motion and optimize stability. However, coefficient of thermal expansion (CTE) mismatch between optical elements, their mountings and the glue may produce large local mechanical stress. Finite element analysis (FEA) was performed to estimate the thermal stress at room temperature and cryogenic temperature (80K). The selection of suitable bonding parameters (gluing setup, glue thickness, etc.) was a challenge given the CTE difference of optical elements (ZnSe and ZerodurTM) and holding flexures (SS304 and InvarTM). Extensive tests were performed to find a suitable bonding strategy. Gluing samples were tested under cryogenic temperature during several weeks. Mechanical shear stress tests were also performed to show that glued assembly could survive a 12g vertical load.
Current high-resolution spectrometers have been designed for seeing-limited sources. Designing a spectrometer for diffraction-limited sources makes it possible to significantly improves its compacity and cost, but it also opens up new concepts, including better efficiency, and adaptability to various spectral domains, and up to very high resolution (several 10^5). A novel, near-IR, R~80000 spectrometer has been developed at IPAG to characterize two sources at once in the H or K bands. Its design is based on a virtually imaged phased array instead of an échelle grating, which allows the spectrometer to fit inside a 0.2m3 cryostat, and results in a gain in throughput with respect to usual échelle spectrographs. One specific science case that can benefit from this new type of design is the characterization of exoplanets' atmosphere. This paper presents the results of its test in the laboratory, as well as the preparation for an on-sky demonstration tentatively scheduled for summer 2020.
KEYWORDS: Spectrographs, Telescopes, Lanthanum, Planets, Spectroscopes, Exoplanets, Aerospace engineering, Space operations, James Webb Space Telescope
NIRPS is a near-infrared (YJH bands), fiber-fed, high-resolution precision radial velocity (pRV) spectrograph currently under construction for deployment at the ESO 3.6-m telescope in La Silla, Chile. Through the use of a dichroic, NIRPS will be operated simultaneously with the optical HARPS pRV spectrograph and will be used to conduct ambitious planet-search and characterization surveys through a 720-night of guaranteed time allocation. NIRPS aims at detecting and characterizing Earth-like planets in the habitable zone of low-mass dwarfs and obtain high-accuracy transit spectroscopy of exoplanets. Here we present a summary of the full performances obtained in laboratory tests conducted at Université Laval (Canada), and the first results of the on-going on-sky commissioning of the front-end. Science operations of NIRPS is expected to start in late-2020, enabling significant synergies with major space and ground instruments such as the JWST, TESS, ALMA, PLATO and the ELT.
Large-format infrared arrays are enablers for a variety of astronomical applications, from wide-field imaging to very high-resolution spectroscopy over a wide range of wavelength. We present the optimization of the science-grade H4RG array used in the SPIRou high-resolution spectrograph designed for high-precision velocity measurements. In SPIRou nominal science operation, the array is used in a relatively low flux regime, well below the full-well of the arrays and, for some applications, the readout noise is a major contributor to the overall signal-to-noise budget. We describe the detector fine-tuning process as well as the derived properties and their impact on performances. We identify persistence as potentially problematic under certain circumstances for infrared m/s velocimetry.
NIRPS (Near Infra Red Planet Searcher) is a new ultra-stable infrared ( YJH) fiber-fed spectrograph that will be installed on ESO’s 3.6-m telescope in La Silla, Chile. Aiming at achieving a precision of 1 m/s, NIRPS is designed to find rocky planets orbiting M dwarfs, and will operate together with HARPS (High Accuracy Radial velocity Planet Searcher). In this paper we describe NIRPS science cases, present its main technical characteristics and its development status.
SPIRou is an innovative near infra-red echelle spectropolarimeter and a high-precision velocimeter for the 3.6 m Canada-France-Hawaii Telescope (CFHT – Mauna Kea, Hawaii). This new generation instrument aims at detecting planetary worlds and Earth-like planets of nearby red dwarfs, in habitable zone, and studying the role of the stellar magnetic field during the process of low-mass stars / planets formation. The cryogenic spectrograph unit, cooled down at 80 K, is a fiber fed double-pass cross dispersed echelle spectrograph which works in the 0.98-2.40 μm wavelength range, allowing the coverage of the YJHK bands in a single exposure. Among the key parameters, a long-term thermal stability better than 2 mK, a relative radial velocity better than 1 m.s -1 and a spectral resolution of 70K are required. After ~ 1 year of assembly, integration and tests at IRAP/OMP (Toulouse, France) during 2016/2017, SPIRou was then shipped to Hawaii and completely re-integrated at CFHT during February 2018. A full instrument first light was performed on 24th of April 2018. The technical commissioning / science validation phase is in progress until June 2018, before opening to the science community. In this paper, we describe the work performed on integration and test of the opto-mechanical assemblies composing the spectrograph unit, firstly in-lab, in Toulouse and then on site, at CFHT. A review of the performances obtained in-lab (in 2017) and during the first on-sky results (in 2018) is also presented.
High-resolution spectroscopy is a key element for present and future astronomical instrumentation. In particular, coupled to high contrast imagers and coronagraphs, high spectral resolution enables higher contrast and has been identified as a very powerful combination to characterise exoplanets, starting from giant planets now, up to Earth-like planet eventually for the future instruments. In this context, we propose the implementation of an innovative echelle spectrometer based on the use of VIPA (Virtually Imaged Phased Array, Shirasaki 1996). The VIPA itself is a particular kind of Fabry-P´erot interferometer, used as an angular disperser with much greater dispersive power than common diffraction grating. The VIPA is an efficient, small component (3 cm × 2.4 cm), that takes the very advantage of single mode injection in a versatile design. The overall instrument presented here is a proof-of-concept of a compact, high-resolution (R > 80 000) spectrometer, dedicated to the H and K bands, in the context of the project “High-Dispersion Coronograhy“ developed at IPAG. The optical bench has a foot-print of 40 cm × 26 cm ; it is fed by two Single-Mode Fibers (SMF), one dedicated to the companion, and one to the star and/or to a calibration channel, and is cooled down to 80 K. This communication first presents the scientific and instrumental context of the project, and the principal merit of single-mode operations in high-resolution spectrometry. After recalling the physical structure of the VIPA and its implementation in an echelle-spectrometer design, it then details the optical design of the spectrometer. In conclusion, further steps (integration, calibration, coupling with adaptive optics) and possible optimization are briefly presented.
Since 1st light in 2002, HARPS has been setting the standard in the exo-planet detection by radial velocity (RV) measurements[1]. Based on this experience, our consortium is developing a high accuracy near-infrared RV spectrograph covering YJH bands to detect and characterize low-mass planets in the habitable zone of M dwarfs. It will allow RV measurements at the 1-m/s level and will look for habitable planets around M- type stars by following up the candidates found by the upcoming space missions TESS, CHEOPS and later PLATO. NIRPS and HARPS, working simultaneously on the ESO 3.6m are bound to become a single powerful high-resolution, high-fidelity spectrograph covering from 0.4 to 1.8 micron. NIRPS will complement HARPS in validating earth-like planets found around G and K-type stars whose signal is at the same order of magnitude than the stellar noise. Because at equal resolving power the overall dimensions of a spectrograph vary linearly with the input beam étendue, spectrograph designed for seeing-limited observations are large and expensive. NIRPS will use a high order adaptive optics system to couple the starlight into a fiber corresponding to 0.4” on the sky as efficiently or better than HARPS or ESPRESSO couple the light 0.9” fiber. This allows the spectrograph to be very compact, more thermally stable and less costly. Using a custom tan(θ)=4 dispersion grating in combination with a start-of-the-art Hawaii4RG detector makes NIRPS very efficient with complete coverage of the YJH bands at 110’000 resolution. NIRPS works in a regime that is in-between the usual multi-mode (MM) where 1000’s of modes propagates in the fiber and the single mode well suited for perfect optical systems. This regime called few-modes regime is prone to modal noise- Results from a significant R and D effort made to characterize and circumvent the modal noise show that this contribution to the performance budget shall not preclude the RV performance to be achieved.
The Near Infrared Imager and Slitless Spectrograph (NIRISS) Optical Simulator (NOS) is a
laboratory simulation of the single-object slitless spectroscopy and aperture masking interferometry modes of the
NIRISS instrument onboard the James Webb Space Telescope (JWST). A transiting exoplanet can be simulated
by periodically eclipsing a small portion (1% - 10ppm) of a super continuum laser source (0.4 μm - 2.4 μm) with
a dichloromethane filled cell. Dichloromethane exhibits multiple absorption features in the near infrared domain
hence the net effect is analogous to the atmospheric absorption features of an exoplanet transiting in front of its
host star. The NOS uses an HAWAII-2RG and an ASIC controller cooled to cryogenic temperatures. A separate
photometric beacon provides a flux reference to monitor laser variations. The telescope jitter can be simulated
using a high-resolution motorized pinhole placed along the optical path. Laboratory transiting spectroscopy data
produced by the NOS will be used to refine analysis methods, characterize the noise due to the jitter, characterize
the noise floor and to develop better observation strategies. We report in this paper the first exoplanet transit
event simulated by the NOS. The performance is currently limited by relatively high thermal background in the
system and high frequency temporal variations of the continuum source.
The CCD282 is a large low-light level (L3 - Electron multiplying CCD) imaging sensor developed by e2v technologies for the University of Montreal. The intended use is for photon counting and very low light level imaging. The device will be used on the 3DNTT instrument which is a scanning Fabry-Perot interferometer. There is also the intention to place a device on a 10m class telescope for scanning Fabry-Perot application. This sensor is the largest electron multiplying CCD device produced to date with a 4k×4k backside illuminated frame transfer architecture. The sensor uses 8 parallel EM (Electron Multiplying) amplified outputs to maximize throughput. This paper present the first results and performance measurements of this device, and especially of the clock induced charge (CIC) which is one order of magnitude lower than previous devices thanks to a specific design optimized for photon counting operation.
SITELLE is an imaging FTS that will become a guest instrument at the Canada-France-Hawaii telescope (CFHT) by the
end of 2014. This paper describes the final optical design of SITELLE, shows how the compliance of the sub-optical
components with the design was evaluated, and presents results of the measured optical quality.
The Gemini Planet Imager (GPI) is a complex optical system designed to directly detect the self-emission of young
planets within two arcseconds of their host stars. After suppressing the starlight with an advanced AO system and
apodized coronagraph, the dominant residual contamination in the focal plane are speckles from the atmosphere and
optical surfaces. Since speckles are diffractive in nature their positions in the field are strongly wavelength dependent,
while an actual companion planet will remain at fixed separation. By comparing multiple images at different
wavelengths taken simultaneously, we can freeze the speckle pattern and extract the planet light adding an order of
magnitude of contrast. To achieve a bandpass of 20%, sufficient to perform speckle suppression, and to observe the
entire two arcsecond field of view at diffraction limited sampling, we designed and built an integral field spectrograph
with extremely low wavefront error and almost no chromatic aberration. The spectrograph is fully cryogenic and
operates in the wavelength range 1 to 2.4 microns with five selectable filters. A prism is used to produce a spectral
resolution of 45 in the primary detection band and maintain high throughput. Based on the OSIRIS spectrograph at
Keck, we selected to use a lenslet-based spectrograph to achieve an rms wavefront error of approximately 25 nm. Over
36,000 spectra are taken simultaneously and reassembled into image cubes that have roughly 192x192 spatial elements
and contain between 11 and 20 spectral channels. The primary dispersion prism can be replaced with a Wollaston prism
for dual polarization measurements. The spectrograph also has a pupil-viewing mode for alignment and calibration.
SPIRou is a near-IR echelle spectropolarimeter and high-precision velocimeter under construction as a next-
generation instrument for the Canada-France-Hawaii-Telescope. It is designed to cover a very wide simultaneous
near-IR spectral range (0.98-2.35 μm) at a resolving power of 73.5K, providing unpolarized and polarized
spectra of low-mass stars at a radial velocity (RV) precision of 1m/s. The main science goals of SPIRou are
the detection of habitable super-Earths around low-mass stars and the study of stellar magnetism of star at
the early stages of their formation. Following a successful final design review in Spring 2014, SPIRou is now
under construction and is scheduled to see first light in late 2017. We present an overview of key aspects of
SPIRou’s optical and mechanical design.
SPIRou is a near-infrared, echelle spectropolarimeter/velocimeter under design for the 3.6m Canada-France-Hawaii
Telescope (CFHT) on Mauna Kea, Hawaii. The unique scientific capabilities and technical design features are described
in the accompanying (eight) papers at this conference. In this paper we focus on the lens design of the optical
spectrograph. The SPIROU spectrograph is a near infrared fiber fed double pass cross dispersed spectrograph. The
cryogenic spectrograph is connected with the Cassegrain unit by the two science fibers. It is also fed by the fiber coming
from the calibration box and RV reference module of the instrument. It includes 2 off-axis parabolas (1 in double pass),
an echelle grating, a train of cross disperser prisms (in double pass), a flat folding mirror, a refractive camera and a
detector. This paper describes the optical design of the spectrograph unit and estimates the performances. In particular,
the echelle grating options are discussed as the goal grating is not available from the market.
KEYWORDS: Stars, Calibration, Control systems, Telescopes, Spectrographs, Sensors, Control systems design, Temperature metrology, Optical benches, Lamps
SPIRou is a near-IR (0.98-2.35μm), echelle spectropolarimeter / high precision velocimeter being designed as a nextgeneration
instrument for the 3.6m Canada-France-Hawaii Telescope on Mauna Kea, Hawaii, with the main goals of
detecting Earth-like planets around low-mass stars and magnetic fields of forming stars. The unique scientific and
technical capabilities of SPIRou are described in a series of eight companion papers. In this paper, the means of
controlling the instrument are discussed. Most of the instrument control is fairly normal, using off-the-shelf components
where possible and reusing already available code for these components. Some aspects, however, are more challenging.
In particular, the paper will focus on the challenges of doing fast (50 Hz) guiding with 30 mas repeatability using the
object being observed as a reference and on thermally stabilizing a large optical bench to a very high precision (~1 mK).μ
The science instrument for GPI (Gemini Planet Imager) is a cryogenic integral field spectrograph
based on a lenslet array. The integral field nature of the instrument allows for a full mapping of the
focal plane at coarse spectral resolution. With such a data cube, artifacts within the PSF such as
residual speckles can be suppressed. Additionally, the initial detection of any candidate planet will
include spectral information that can be used to distinguish it from a background object: candidates
can be followed up with detailed spectroscopic observations. The optics between the lenslet array
and the detector are essentially a standard spectrograph with a collimating set of lenses, a dispersive
prism and a camera set of lenses in a folded assembly. We generally refer to this optical set as the
spectrograph optics. This paper describes the laboratory optical performances over the field of view.
The test procedure includes the imaging performances in both non dispersive and dispersive mode.
The test support equipments include a test cryostat, an illumination module with monochromatic
fiber laser, a wideband light source and a test detector module.
The 3D-NTT is a visible integral field spectro-imager offering two modes. A low resolution mode (R ~ 300 to 6 000)
with a large field of view Tunable Filter (17'x17') and a high resolution mode (R ~ 10 000 to 40 000)
with a scanning Fabry-Perot (7'x7'). It will be operated as a visitor instrument on the NTT from 2009.
Two large programmes will be led: "Characterizing the interstellar medium of nearby galaxies with 2D maps of
extinction and abundances" (PI M. Marcelin) and "Gas accretion and radiative feedback in the early universe" (PI J.
Bland Hawthorn). Both will be mainly based on the Tunable Filter mode. This instrument is being built as a
collaborative effort between LAM (Marseille), GEPI (Paris) and LAE (Montreal). The website adress of the instrument
is : http://www.astro.umontreal.ca/3DNTT
CPAPIR is a wide-field infrared camera for use at the Observatoire du mont Megantic and CTIO 1.5 m telescopes. The camera will be primarily a survey instrument with a half-degree field of view, making it one of the most efficient of its kind. CPAPIR will provide broad and narrow band filters within its 0.8 to 2.5 μm bandpass. The camera is based on a Hawaii-2 2048x2048 HgCdTe detector.
WIRCam (Wide-field InfraRed Camera) is a near-infrared (0.9-2.4 microns) camera developed for the prime focus of the Canada France Hawaii Telescope (CFHT), a 3.6-m telescope located on Mauna Kea, Hawaii. WIRCam is based on 4 x 2048x2048 HAWAII2RG arrays, developed by Rockwell. The camera provides a 0.3"/pixel sampling, and the close packaging of the detectors allows to cover an almost contiguous field-of-view of 20.5' x 20.5'. All optical elements are assembled in a cryovessel and cooled down to 85K by a He closed cycle cryogenerator. The two filter wheels have capacity for 8 filters (110 mm in diameter), cooled at low temperature together with the Lyot stop. These wheels are mounted on sapphire ball bearings and powered by external motors. Passive spring indexers define their positioning. A fused-silica tip/tilt plate powered by voice coil type motors provides image stabilization in front of the cryovessel. It compensates for flexures as well as for low frequency telescope oscillations from wind shake. This paper describes the overall architecture of the camera, giving the optical estimated performances and details some specific points of the design such as filter wheels, thermal connections, etc.
A wide-field near-infrared (0.8 - 2.4 μm) camera for the 1.6 m telescope of the Observatoire du mont Megantic (OMM), is currently under construction at the Universite de Montreal. The field of view is 30' × 30' and will have very little distortion. The optics comprise 8 spherical cryogenic lenses. The instrument features two filter wheels with provision for 10 filters including broad band I, z, J, H, K and other narrow-band filters. The camera is based on a 2048 × 2048 HgCdTe Hawaii-2 detector driven by a 3--output SDSU-II controller operating at ~250 kHz.
The Laboratoire d'Astrophysique Experimentale (LAE) at the Universite de Montreal has designed and built several near-infrared cameras/spectrometers in the last decade for the Observatoire du Mont-Mégantic (OMM), the Canada-France-Hawaii Telescope (CFHT) and the Herzberg Institute of Astrophysics (HIA). These instruments have required innovative solutions for cryogenic electro-mechanical controls. This paper presents cryogenic motors, bearings, gears, epoxies and positioning/sensing devices at the heart of these cryo-mechanisms. In particular, the paper will focus on a new ball plunger with integrated Hall effect sensor, which can be used both as a mechanical detent and analog position encoder.
In this paper, we present the final design of the optical train of WIRCAM, a wide-field infrared camera to be installed in early 2004 at the prime focus of CFHT. This cryogenic camera, optimized for J, H and K operating region, used a 4k x 4k IR detector mosaic fed by a single optical train. The sky will be imaged onto the focal plane at an optical speed of F/3.5 yielding an image scale of 0.3 arcsecond per 18 μm pixel. The design image quality is 0.30 arcsecond 50% diffraction encircled energy over the central 20 arcmin field and no images worse than 0.35 arcsecond over the 29.7 arcminute diameter camera field. The optical design distortion at the corners is less than 1%. The WIRCAM camera have a lyot stop at the telescope image pupil in order to mask background radiation coming from external structures. The image of the pupil is sufficiently sharp for background elimination and impose not more than 2% loss of light from the sky in the K spectral band. We also present an optimization of AR coating for IR based camera weighted by MK atmospheric transmission. We discuss the impact of this coating design method on various camera throughput. We include an efficient technique for ghost analysis based on the detector image. We demonstrate that our design meets the performance requirements from an optical and practical point of view.
A near-infrared camera in use at the Canada-France-Hawaii Telescope and at the 1.6m telescope of the Observatoire du Mont-Mégantic is described. The camera is based on a Hawaii-1 1024×1024 HgCdTe array detector. Its main feature is to acquire three simultaneous images at three wavelengths (simultaneous differential imaging) across the methane absorption bandhead at 1.6 micron, enabling an accurate subtraction of the stellar point spread function (PSF) and the detection of faint close methanated companions. The instrument has no coronagraph and features a fast (1 MHz) data acquisition system without reset anomaly, yielding high observing efficiencies on bright stars. The performance of the instrument is described, and it is illustrated by CFHT images of the nearby star Ups And. TRIDENT can detect (3 sigma) a methanated companion with Delta H=10 at 0.5” from the star in one hour of observing time. Non-common path aberrations between the three optical paths are the limiting factors preventing further PSF attenuation. Reference star subtraction and instrument rotation improve the detection limit by one order of magnitude.
The optical design of the wide-field infrared camera CPAPIR (Camera PAnoramique Proche InfraRouge) for the Mont Megantic Observatory (OMM) has been completed. CPAPIR will be a unique wide-field camera at the OMM. It has a full field of view of 0.71 degrees, an instantaneous field of view of 0.88 arc-seconds, and a spectral coverage of 0.85 - 2.5 μm. The camera is operated under vacuum and at cryogenic temperature. The performance (image quality, vignetting, cold stop efficiency, ghost analysis and tolerancing) of CPAPIR has been optimized at cold temperature using cryogenic indices of refraction and coefficients of thermal.
We present the preliminary conceptual design of a Mosaic IR Camera and Multi-Object Spectrography (MIRCAMOS) for the Canada-France-Hawaii Telescope. The instrument houses 4 Hawaii-2 2048 by 2048 HgCdTe detectors sensitive between 0.8 and 2.5 micrometers . The optics is all reflective, featuring a warm corrector with fast tip/tilt capability and 4 cryogenic optical trains. The pixel scale is 0.20 inch/pixel yielding a field of view of 13.7 feet by 13.7 feet. Z, J, H or K band spectroscopy at R approximately 1500 is obtained with a single grating setting. A cryogenic slit wheel unit featuring several positions for multi-object custom masks is mounted within a separate cryostat designed to be thermally cycled within 8 hours for rapid exchange of MOS masks. Each mask can hold up to approximately 300 slitlets distributed over a FOV of 7 feet by 13.7 feet. MIRCAMOS is very competitive compared with similar instruments planned for 8- 10 m telescopes.
The CFHTIR is a large format near IR camera based on the Rockwell HAWAII Array. CFHTIR is designed for both direct imaging at the f/8 Cassegrain focus, as well as spectroscopy on the OSIS multiobject spectrograph. The camera provides 0.21 inch/pixel sampling in both applications with a single set cold transfer optics and pupil mask. The camera includes two eight-position filterwheels driven by cryogenic stepper motors with position control using a novel Hall effect sensor technique. CFHTIR also uses a novel dewar wiring technique employing flexible circuit vacuum feedthrus. CFHTIR is the second large format IR camera based on the Hawaii array constructed at CFHT, the first being the KIR camera for the CFHT Adaptive Optics Bonnette which was commissioned in 1997. This paper describes the system architecture of the CFHTIR highlighting key design concepts and detailing the physical elements.
KIR is a 1024 by 1024 near-IR camera used with the adaptive optics Bonnette (PUEO) of the Canada-France-Hawaii Telescope. The camera houses a 1024 by 1024 HgCdTe and simple refractive optics providing diffraction-limited images with an image scale of 0.035 inch/pixel. First light was obtained in December 1997. The throughput of the camera, from the top of the atmosphere down to the atmosphere down to the detector including PUEO, is 19 percent, 20 percent and 21 percent at J, H and K, respectively. This project is a collaboration between the Universite de Montreal, the Observatoire Midi Pyrenees and the Canada-France-Hawaii Telescope. The design and performance of the instrument are presented in this paper.
SIMON (`Spectrometre Infrarouge de Montreal') is a near-infrared (1.0 micrometers to 2.5 micrometers ) camera/spectrometer currently under development at the Universite de Montreal. The instrument will be used on the 3.6 m Canada-France-Hawaii telescope (CFHT) and the 1.6 m telescope of the Observatoire du Monte Megantic (OMM). It will house a 1024 MUL 1024 array with an image scale of 0.15" on the CHFT and 0.34" on the OMM. Two long-slit spectroscopic modes will provide resolving powers of 1300 and 5000 from 1.0 micrometers to 2.5 micrometers . The instrument could be interfaced with the adaptive optics system currently under development at the CFHT, providing diffraction-limited images at J, H, and K. This paper describes the general characteristics and the optical design of the instrument.
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