Optimizing the night time is essential on a site like Maunakea. The mountain offers excellent weather conditions that can be used to observe more programs than most sites in the world. CFHT has been making significant efforts toward optimal usage of the night time, starting in 2000 with the implementation of the Queued Service Observing (QSO) system followed by the installation of the dome vents in 2012 and lastly, the implementation of the Signal to Noise Ratio (SNR) observing mode in 2013. The QSO-SNR mode is now used by default at CFHT for two of our instruments: MegaCam, a one square degree imager, and ESPaDOnS, a high resolution spectropolarimeter. This paper describes the implementation strategy for each instrument as well as the time saved using this observing mode.
The SITELLE Imaging Fourier Transform Spectrometer was successfully commissioned at the Canada France Hawaii Telescope starting in July 2015. Here we discuss the commissioning process, the outcome of the early tests on-sky as well as the ensuing work to optimize the modulation efficiency at large optical path difference and the image quality of the instrument.
Proc. SPIE. 9910, Observatory Operations: Strategies, Processes, and Systems VI
KEYWORDS: Signal to noise ratio, Signal to noise ratio, Point spread functions, Astronomy, Sensors, Spectroscopy, Interference (communication), Imaging spectroscopy, Coronagraphy, Signal detection, James Webb Space Telescope
In an effort to optimize the night time utilizing the exquisite weather on Maunakea, CFHT has equipped its dome with vents and is now moving its Queued Scheduled Observing (QSO)1 based operations toward Signal to Noise Ratio (SNR) observing. In this new mode, individual exposure times for a science program are estimated using a model that uses measurements of the weather conditions as input and the science program is considered completed when the depth required by the scientific requirements are reached. These changes allow CFHT to make better use of the excellent seeing conditions provided by Maunakea, allowing us to complete programs in a shorter time than allocated to the science programs.
The Maunakea Spectroscopic Explorer (MSE; formerly ngCFHT) will be a large format wide field spectroscopic facility that replaces the existing 3.6 m Canada-France-Hawaii Telescope. Capable of recording tens of thousands of spectra on faint targets each night, and sustain that pace for years, MSE will be an ideal complement to emerging space- and ground-based imaging survey facilities. The combination of aperture, spectral resolution, and dedicated access to support large surveys makes MSE distinct from any other facilities under development or being planned. We provide an overview of the MSE technical design, organization of the project office, and the core science goals that will help drive MSE for decades.
OPERA is a Canada-France-Hawaii Telescope (CFHT) open source collaborative software project currently under
development for an ESPaDOnS echelle spectro-polarimetric image reduction pipeline. OPERA is designed to be
fully automated, performing calibrations and reduction, producing one-dimensional intensity and polarimetric
spectra. The calibrations are performed on two-dimensional images. Spectra are extracted using an optimal
extraction algorithm. While primarily designed for CFHT ESPaDOnS data, the pipeline is being written to be
extensible to other echelle spectrographs. A primary design goal is to make use of fast, modern object-oriented
technologies. Processing is controlled by a harness, which manages a set of processing modules, that make use
of a collection of native OPERA software libraries and standard external software libraries. The harness and
modules are completely parametrized by site configuration and instrument parameters. The software is open-
ended, permitting users of OPERA to extend the pipeline capabilities. All these features have been designed to
provide a portable infrastructure that facilitates collaborative development, code re-usability and extensibility.
OPERA is free software with support for both GNU/Linux and MacOSX platforms. The pipeline is hosted on
SourceForge under the name "opera-pipeline".
A concept study is underway to upgrade the existing 3.6 meter Canada-France-Hawaii Telescope (CFHT) to a
10 meter class, wide-field, dedicated, spectroscopic facility, which will be the sole astronomical resource capable
of obtaining deep, spectroscopic follow-up data to the wealth of photometric and astrometric surveys planned
for the next decade, and which is designed to tackle driving science questions on the formation of the Milky Way
galaxy and the characterization and nature of dark energy. This unique facility will operate at low (R ∼ 2000),
intermediate (R ∼ 6000) and high (R ∼ 20000) resolutions over the wavelength range 370 ≤ λ≤ 1300nm,
and will obtain up to 3200 simultaneous spectra per pointing over a 1.5 square degree field. Unlike all other
proposed or planned wide field spectroscopic facilities, this “Next Generation CFHT” will combine the power
of a 10m aperture with exquisite observing conditions and a mandate for dedicated spectroscopic studies to
enable transformative science programs in fields as diverse as exoplanetary host characterization, the interstellar
medium, stars and stellar astrophysics, the Milky Way galaxy, the Local Group, nearby galaxies and
clusters, galaxy evolution, the inter-galactic medium, dark energy and cosmology. A new collaboration must
be formed to make this necessary facility into a reality, and currently nearly 60 scientists from 11 different
communities - Australia, Brazil, Canada, China, France, Hawaii, India, Japan, South Korea, Taiwan, USA - are
involved in defining the science requirements and survey strategies. Here, we discuss the origins of this project,
its motivations, the key science and its flow-down requirements. An accompanying article describes the technical
studies completed to date. The final concept study will be submitted to the CFHT Board and Science Advisory
Committee in Fall 2012, with first light for the facility aiming to be in the early 2020s.
We present a new observing mode using WirCam on the Canada-France-Hawaii Telescope (CFHT). The staring mode with WIRCam can observe a target for several hours on the same pixels of the array. This allows for characterization of the photometric variations of the target to less than 0.02%, or to a signal-to-Noise Ratio ≥
5000. The technical challenges encountered to implement this mode are described as well as a simple model to estimate the idealized performance of this observing mode. Early results are also presented and compared to the models.
The Wide field Infrared Camera (WIRCam) is one of the 3 workhorse instruments in operation at CFHT. It's
mosaic of four HAWAII-2RG is read using two SDSU-III controllers with 32-amplifiers in parallel per detector.
First-light images showed that WIRCam suffered from three flavors of cross-talk: the "positive", "negative" and
"edge" cross-talks. All have now been eliminated at the source and WIRCam is now cross-talk free. Two of
these cross-talks originated from the controller electronic and one, the "edge" cross-talk, is intimately linked
to the HAWAII-2RG detector and its description may be of a broader interest for other instruments using
these detectors. We present the three cross-talk flavors and the hardware or software solutions implemented to
We present an analysis of the behavior of the detectors on the Infrared Spectrograph (IRS)<sup>1</sup> onboard Spitzer.<sup>2</sup>
The detectors of the IRS have been subjected to a 2.5 years of harsh space environments. We found that the
number of protons hitting the IRS detectors is approximately 1 every second. We also present a simple analysis
that shows that the Si:Sb detectors are about a factor 3 to 6 times more sensitive to the space environment than
the Si:As detectors.
During the in-orbit checkout phase of the Infrared Spectrograph on board The Spitzer Telescope, it was found that the noise of the spectrograph's arrays was correlated with the number of cosmic ray hits. Our analysis reveals that the cause of that effect is most likely due to the algorithms used to correct cosmic ray hits on dark pixels. We also found that the noise characteristics of the pixels that have an illumination that is lower than 1/10 of the full well is artificially raised by the cosmic ray correction by a factor of about 10% if 1% of the pixels are affected by cosmic rays.
The Infrared Spectrograph (IRS) is one of three science instruments on the Spitzer Space Telescope. The IRS comprises four separate spectrograph modules covering the wavelength range from 5.3 to 38 μm with spectral resolutions, R~90 and 650, and it was optimized to take full advantage of the very low background in the space environment. The IRS is performing at or better than the pre-launch predictions. An autonomous target acquisition capability enables the IRS to locate the mid-infrared centroid of a source, providing the information so that the spacecraft can accurately offset that centroid to a selected slit. This feature is particularly useful when taking spectra of sources with poorly known coordinates. An automated data reduction pipeline has been developed at the Spitzer Science Center.