MSE is a massively multiplexed spectroscopic survey facility that will replace the Canada-France-Hawaii-Telescope in the coming decade. This 12-m plus telescope, with its 1.5-2.0 square degree field-of-view, will observe 18,720 astronomical targets at every pointing with nominal specifications including: wavelength range equal to 360 nm through 1.8 microns (H-band); low/moderate resolution (R=3,000/7,000) or high resolution (R=30,000). MSE will contribute to nearly every field of astrophysics across all spatial scales, from individual stars to the largest scale structures in the Universe, including (i) the ultimate Gaia follow-up facility for understanding the chemistry and dynamics of the Milky Way, including the outer disk and faint stellar halo (ii) galaxy formation and evolution at cosmic noon, (iii) derivation of the mass of the neutrino and insights into inflationary physics through a cosmological redshift survey that probes a large volume of the Universe. The instrument suite, dedicated to large-scale surveys, will enable MSE to collect massive data, equivalent to a full SDSS Legacy Survey every several weeks. We present an update to the MSE specifications, requirements and technology.
Working in harmony with Wenaokeao, a combination of the ESPaDOnS and SPIROU visible and infrared spectropolarimeters, an IFU at CFHT would complete a spectrographic instrument suite with broad application, welltailored to the rapid follow-up observations of newly discovered multi-messenger targets. The CFHT IFU will leverage the DESI spectrograph design, baselining a single ~500 fiber array feeding one DESI spectrograph, with the possibility of future upgrade to a second identical IFU and spectrograph. The IFU will have a 3' patrol field allowing it to be used simultaneously with Wenaokeao on deep objects requiring long integration times, possibly over repeated visits, over a field subordinate to the primary target defined by the Wenaokeao observations. This paper describes a preliminary concept for the IFU format, the off-axis coma corrector, ADC, and transfer optics needed to efficiently couple light into the spectrograph.
Maunakea Spectroscopic Explorer (MSE) is a telescope dedicated to multi-fibers spectroscopy and IFUs observations of the sky. Program Execution System Architecture (PESA) is one of the systems of MSE, responsible for planning, executing, reducing, and distributing science products from survey programs. Work is being done to design PESA in a modular way to include several sophisticated software tools, organized into an operational framework. This paper describes the first step of its organization and the concepts that will be used in the development of PESA.
MegaCam has been CFHT's one-degree wide-field optical imager and primary dark time instrument since 2003. After nearly twenty years of operation, demand for the instrument remains high, but maintenance has been a challenge as many electronic components have become obsolete and difficult to find. Other off-the-shelf assemblies, such as the S-LINK data transmission pair for the CCD controllers from CERN (European Organization for Nuclear Research), are also no longer available and cannot be repaired. Ongoing failures, only one working spare, and a lack of a plug-n-play upgrade path forced the development of an alternative solution.
The Maunakea Spectroscopic Explorer (MSE) will obtain millions of spectra each year in the optical to near-infrared, at low (R ≃ 3; 000) to high (R ≃ 40; 000) spectral resolution by observing <4,000 spectra per pointing via a highly multiplexed fiber-fed system. Key science programs for MSE include black hole reverberation mapping, stellar population analysis of faint galaxies at high redshift, and sub-km/s velocity accuracy for stellar astrophysics.
One key metric of the success of MSE will be its survey speed, i.e. how many spectra of good signal-to-noise ratio will MSE be able to obtain every night and every year. This is defined at the higher level by the observing efficiency of the observatory and should be at least 80%, as indicated in the Science Requirements.
In this paper we present the observing efficiency budget developed for MSE based on historical data at the Canada-France-Hawaii Telescope and other Maunakea Observatories. We describe the typical sequence of events at night to help us compute the observing efficiency and how we envision to optimize it to meet the science requirements
SPIRou (SpectroPolarimètre Infra-Rouge in French), is a near-infrared, fiber-fed spectropolarimeter at the CanadaFrance-Hawaii Telescope (CFHT) which gives full spectral coverage from 0.98 to 2.35 μm with a resolving power of 70,000. The main science drivers for SPIRou are (i) detecting and characterizing exoplanets around nearby M dwarfs through high-precision (1 m/s) velocimetry, and (ii) investigating the impact of magnetic fields on star/planet formation through spectropolarimetry. One of the requirements for achieving this challenging radial velocity (RV) precision is ensuring that the observed star does not move with respect to the instrument entrance aperture by more than 0.05 arcseconds RMS over the course of the observation. This is complicated by the fact that the guiding uses light from the science target so that only about 13% of the light (10% from the wings and 3% from the core) is available in seeing conditions of 0.65 arc-seconds in H band. To achieve this level of guiding accuracy, a fast guiding system has been implemented in the injection module of the instrument. This paper describes the system, its performance in tests on the sky with the CFHT since the delivery of SPIRou in January 2018, and gives comparisons to laboratory measurements and simulations.
KEYWORDS: Charge-coupled devices, Digital signal processing, Data acquisition, Image filtering, Signal to noise ratio, Telescopes, Clocks, Data conversion, Sensors, Amplifiers
MegaCam is Canada-France-Hawaii Telescope’s (CFHT) one-degree wide-field optical imager with an array of 40 CCDs that has been in operation since 2003 and remains the most demanded instrument at CFHT with an oversubscription of 2.5 each semester. Large programs requiring hundreds of nights dominate the available observing time leaving little for PI programs. To accommodate the demand and to improve overall observing efficiency, we launched the MegaCam FAST project to reduce the data acquisition time.
The Canada-France-Hawaii Telescope (CFHT) completed the first phase of its TCS upgrade in early 2015. Prior to this effort, the previous version of CFHTs TCS was largely unmodified since it began operation in 1979 and had begun to exhibit reliability and maintainability issues entering its third decade of operation. The first phase consisted of replacing the custom-built servo control hardware built by the Canadian Marconi Company with an off-the-shelf Delta Tau Systems Power PMAC and replacing the absolute and incremental encoders with modern equivalents. Adapting the motion control algorithms used within the Power PMAC for real-time control of the telescope on the sky posed unique challenges. This work brie y summarizes the design for the upgraded TCS at CFHT, describes the solutions that adapted the traditional use of the Power PMAC for use at CFHT, and discusses the improved performance of CFHTs new TCS in terms of decreased time to target and tracking error.
The Maunakea Spectroscopic Explorer is designed to be the largest non-ELT optical/NIR astronomical telescope, and will be a fully dedicated facility for multi-object spectroscopy over a broad range of spectral resolutions. The MSE design has progressed from feasibility concept into its current baseline design where the system configuration of main systems such as telescope, enclosure, summit facilities and instrument are fully defined. This paper will describe the engineering development of the main systems, and discuss the trade studies to determine the optimal telescope and multiplexing designs and how their findings are incorporated in the current baseline design.
The Canada-France-Hawaii Telescope is currently in the conceptual design phase to redevelop its facility into the new Maunakea Spectroscopic Explorer (MSE). MSE is designed to be the largest non-ELT optical/NIR astronomical telescope, and will be a fully dedicated facility for multi-object spectroscopy over a broad range of spectral resolutions. This paper outlines the software and control architecture envisioned for the new facility. The architecture will be designed around much of the existing software infrastructure currently used at CFHT as well as the latest proven opensource software. CFHT plans to minimize risk and development time by leveraging existing technology.
KEYWORDS: Camera shutters, Inspection, Control systems, Failure analysis, Observatories, Video, Switches, Data modeling, Photonic integrated circuits, Iron
The dome shutter drive system for the CFHT observatory experienced two, separate, catastrophic failures recently (15 DEC 11) and (14 APR 12); leading to a full-blown, company-wide investigation to understand and determine the root cause of both failures. Multiple resources were utilized to detect and reveal clues to help determine the cause of failure. Former colleagues were consulted, video footage investigated, ammeter plots dissected, solid models developed, forensic analysis of failed parts performed, controller mock-up established; all in an attempt to gather data, better understand the system, and develop a clear path solution to resurrect the shutter and return it to normal operation. My paper will attempt to describe in detail the problems encountered, investigations performed, analysis developed, and solutions integrated.
As part of the image quality (IQ) assessment and improvement initiative being carried out at the 3.6m Canada
France Hawaii Telescope (CFHT) on Mauna Kea, Hawaii, our objective in the work reported here is to obtain
a systematic assay of thermal sources within the dome and in the summit environment around the observatory,
and therefore mitigate their contributions to convective instability leading to 'dome seeing'. Toward this, we
undertook a nighttime overflight to capture thermal images with a calibrated infrared camera of the outer
structures of CFHT and the neighboring observatories on the summit ridge, as well as of a significant area
of the surrounding terrain. The same thermal camera was then used to image heat sources within the dome.
Using a convective heat transfer model, all these measured surface temperatures were converted to heat fluxes,
and thus used to build a thermal assay of the dome. In addition, using button type temperature loggers, we
simultaneously recorded the nighttime dome skin temperatures of CFHT and two other observatories over a
weeklong period to evaluate nighttime supercooling of the dome skin due to radiation to the cold night sky. As a
complementary goal we compared the efficacy of different paints and coatings used in observatories to minimize
this effect. Though similar studies have been carried out at other observatories, the results are rarely available
in published literature. Therefore, here we explain our methodologies, along with a detailed discussion of our
results and inferences to serve as a useful resource to the larger observing community.
The Canada-France-Hawaii Telescope (CFHT) has been in operation since 1979. The Telescope Control System (TCS)
has undergone software changes since the beginning of science operation but the original hardware has largely been
untouched except for an upgrade to the time system and host computer. Telescope performance has not been an issue
although some improvements are desirable. However, parts obsolescence will become a problem as the telescope enters
it third decade of operation. Although there are sufficient spare parts currently, many are no longer readily available.
Some critical components, such as encoders and VME CPU boards are no longer available. The TCS upgrade project
addresses the obsolete and obsolescent issues to ensure operational capability through 2025. It seeks to modernize and
simplify the electronics and to take advantages of the advancement made in stand-alone servo controllers.
Ground-layer adaptive optics (GLAO) has the potential to dramatically increase the efficiency and capabilities of
existing ground-based telescopes over a broad range of astronomical science. Recent studies of the optical turbulence
above several astronomical sites (e.g. Mauna Kea, Paranal, and Antarctica) show that GLAO can be extended to fields of
view of several tens of arcminutes in diameter, larger than previously thought, with angular resolutions close to the freeatmosphere
seeing. This is a pivotal result since GLAO science cases benefit from the largest possible corrected fields
of view. The corrected areal field of a GLAO system is potentially 2-3 orders of magnitude larger than has been
demonstrated to date. The 'Imaka team is working toward an instrument that takes advantage of the one-degree field
afforded by Mauna Kea. In this paper we summarize the design/simulation work to date along with our plan to develop
an instrument that reaches for this wide field of view.
The SITELLE Imaging Fourier Transform Spectrometer system being developed by l'Université Laval at ABB-Bomem
will require two identical CCD detector systems. Our requirements for the cryogenic system for these cameras are:
cooling to below 190 K, extremely low vibrational input from the cryogenic system (<1 mg RMS from 0-2 kHz), hands-off
operation over long periods of time and low original capital outlay and continued operation cost. These constraints
drove towards the selection of a Polycold PCC cooled system which exhibits relatively low vibrational noise and can
efficiently achieve the required cooling power in our target temperature range. This paper will present work performed
to passively mitigate high frequency vibrations imparted by the Polycold PCC cryo-head on the detector cryostat.
The 'Imaka project is a high-resolution wide-field imager proposed for the Canada-France-Hawaii telescope
(CFHT) on Mauna Kea. 'Imaka takes advantage of two features of the optical turbulence above Mauna Kea:
weak optical turbulence in the free-atmosphere and boundary layer turbulence which is highly confined within a
surface layer tens of meters thick and or the telescope enclosures. The combination of the two allows a groundlayer
adaptive optics system (GLAO) to routinely deliver an extremely-wide corrected field of view of one-degree
at an excellent free-atmosphere seeing limit at visible wavelengths. In addition, populating the focal-plane with
orthogonal-transfer CCDs provides a second level of image improvement on the free-atmosphere seeing and the
residual GLAO correction. The impact of such an instrument covers a broad range of science and is a natural
progression of CFHT's wide-field expertise.
VASAO is an ambitious project that explores new conceptual direction in the field of astronomical adaptive optics. In
the era of 8 meter and larger telescopes, and their instrument costs and telescope time pressure, there is a natural niche
for such ground-breaking conceptual development in the 4 meter class telescope. The aim of VASAO is to provide
diffraction limited imaging in the visible with 100% sky coverage; the challenge (but potential rewards) arises from the
simultaneity of these requirements. To this end, CFHT is conducting a feasibility study based on the polychromatic
guide star concept (Foy et al., 1995 [4]) coupled with a high order curvature AO system, presented in this paper.
A number of experiments have been started (or carried out) to study the challenges and limits of the techniques involved
in an operational setting; these include the FlyEyes detector, and a polychromatic tip-tilt test on natural stars.
Because such a project straddles such a fine line between facility instrument and experimental facility, careful thought
has to be given to the balance between modes of operations and potential astrophysical targets.
C. Juramy, E. Barrelet, K. Schahmaneche, P. Bailly, W. Bertoli, C. Evrard, P. Ghislain, A. Guimard, J.-F. Huppert, D. Imbault, D. Laporte, H. Lebbolo, P. Repain, R. Sefri, A. Vallereau, D. Vincent, P. Antilogus, P. Astier, J. Guy, R. Pain, N. Regnault, R. Attapatu, T. Benedict, G. Barrick, J.-C. Cuillandre, S. Gajadhar, K. Ho, D. Salmon
We present the first results of the SuperNova Direct Illumination Calibration Experiment (SNDICE), installed
in January 2008 at the Canada France Hawaii Telescope. SNDICE is designed for the absolute calibration of
the instrumental response of a telescope in general, and for the control of systematic errors in the SuperNova
Legacy Survey (SNLS) on Megacam in particular. Since photometric calibration will a critical ingredient for
the cosmological results of future experiments involving instruments with large focal planes (like SNAP, LSST
and DUNE), SNDICE functions also as a real-size demonstrator for such a system of instrumental calibration.
SNDICE includes a calibrated source of 24 LEDs, chosen for their stability, spectral coverage, and their power,
sufficient for a flux of at least 100 electron/s/pixel on the camera. It includes also Cooled Large Area Photodiode
modules (CLAPs), which give a redundant measurement of the flux near the camera focal plane. Before installing
SNDICE on CFHT, we completed a full calibration of both subsystems, including a spectral relative calibration
and a 3D mapping of the beam emitted by each LED. At CFHT, SNDICE can be operated both to obtain a
complete one-shot absolute calibration of telescope transmission in all wavelengths for all filters with several
incident angles, and to monitor variations on different time scales.
A project to upgrade PUEO, the CFHT AO system, was first proposed in 2002. As part of the upgrade effort, a
technology project was conceived to evaluate and characterize the backside-illuminated CCID-35 detector as suitable a
replacement for the array of avalanche photo diode modules (APDs) in the curvature wavefront sensor. The CCID-35
was envisioned to replace an array of expensive APDs thus providing a cost-effective means of upgrading PUEO to a
higher-order system. Work on the project, dubbed FlyEyes, occurred sporadically until Oct 2005 but substantial
progress has been made since. This paper was intended to report on the performance of FlyEyes in PUEO but
unfortunately the instrument was not ready for tests at the time of this writing. This paper summarizes the progress
made on the project thus far and touches upon some of the difficulties encountered.
CFHT is planning to upgrade its adaptive optics system, PUEO, to a high order system with 104 elements, PUEO NUI. Currently PUEO uses a 19 element deformable mirror with the equivalent 19 avalanche photodiode (APD) detectors as its curvature wavefront sensor. PUEO NUI plans to implement the curvature wavefront sensor using back illuminated CCID-35 detectors developed by J. Beletic et al. instead of 104 APDs, which are prohibitively expensive under the present budget conditions. The CCID-35 detectors, developed at ESO and MIT/LL, were specifically designed to serve as direct replacements for APDs in curvature sensing. The first step in the upgrade is to build and test a system using two CCID-35 detectors, dubbed FlyEyes. These new detectors were successfully tested and integrated in the lab by R. Dorn at ESO but have yet to see sky time. FlyEyes will be their first opportunity. They will directly replace the 19 APDs in PUEO temporarily for a few engineering nights in January of 2005.
The adaptive optics system design for the W. M. Keck Telescope incorporates over twenty tracking and movable stages on the optical bench. This paper presents a commercial solution for controlling and positioning these stages. It describes the hardware system and the EPICS software interface used to communicate with the off the shelf hardware controllers. It touches on the positional accuracy and repeatability requirements and the selection of hardware to meet those requirements. It examines the cost and packaging issues and tradeoffs between developing custom hardware and software versus commercially available equipment. A method of synchronizing the stages to absolute time for telescope tracking is also presented.
The servo design and model of the W. M. Keck telescopes autoguider is presented. Telescope servo models often do not include the guider loop and therefore do not take advantage of traditional control analysis and test techniques to improve performance. Guide camera dynamics, computational and transport lags, and compensation networks are discussed. A means of measuring the actual frequency response characteristics of the guide loop is presented and the results are compared to those predicted by the model. Guide performance as a function of integration time is illustrated. An improved compensation network is developed and its performance examined.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.