The instrumentation of the Prime Focus Spectrograph (PFS), a next generation facility instrument on the Subaru telescope, is now in the final phase of its commissioning process and its general, open-use operations for sciences will provisionally start in 2025. The instrument enables simultaneous spectroscopy with 2386 individual fibers distributed over a very wide (∼1.3 degrees in diameter) field of view on the Subaru’s prime focus. The spectra cover a wide range of wavelengths from 380nm to 1260nm in one exposure in the Low-Resolution (LR) mode (while the visible red channel has the Medium-Resolution (MR) mode as well that covers 710−885nm). The system integration activities at the observatory on Maunakea in Hawaii have been continuing since the arrival of the Metrology Camera System in 2018. On-sky engineering tests and observations have also been carried out continually since September 2021 and, despite various difficulties in interlacing commissioning processes with development activities on the schedule and addressing some major issues on hardware and software, the team successfully observed many targeted stars as intended over the entire field of view (Engineering First Light) in September 2022. Then in parallel to the arrival, integration and commissioning of more hardware components, validations and optimizations of the performance and operation of the instrument are ongoing. The accuracy of the fiber positioning process and the speed of the fiber reconfiguration process have been recently confirmed to be ∼ 20−30μm for 95% of allocated fibers, and ∼130 seconds, respectively. While precise quantitative analyses are still in progress, the measured throughput has been confirmed to be consistent with the model where the information from various sub-components and sub-assemblies is integrated. Long integration of relatively faint objects are being taken to validate an expected increase of signal-to-noise ratio as more exposures are taken and co-added without any serious systematic errors from, e.g., sky subtraction process. The PFS science operation will be carried out in a queue mode by default and various developments, implementations and validations have been underway accordingly in parallel to the instrument commissioning activities. Meetings and sessions are arranged continually with the communities of potential PFS users on multiple scales, and discussions are iterated for mutual understanding and possible optimization of the rules and procedures over a wide range of processes such as proposal submission, observation planning, data acquisition and data delivery. The end-to-end processes of queue observations including successive exposures with updated plans based on assessed qualities of the data from past observations are being tested during engineering observations, and further optimizations are being undertaken. In this contribution, a top-level summary of these achievements and ongoing progresses and future perspectives will be provided.
ULTIMATE-Subaru is the next-generation facility instrument program of the Subaru Telescope which will extend the existing Subaru’s wide-field survey capability to the near-infrared wavelength. The ULTIMATE-Subaru instrument suite includes Ground-Layer Adaptive Optics (GLAO) and wide-field near-infrared instruments, aiming to provide ∼0.2 arcsec image size at K band (2.2 μm) over 20 arcmin diameter field of view at the Cassegrain focus. The planned first light instrument is a Wide-Field Imager (WFI), which covers a 14 × 14 square arcmin field of view from 0.9 to 2.5 μm in wavelength. GLAO and WFI are currently in the final design phase, aiming to start the commissioning observations at the telescope in 2028. In parallel to the development for ULTIMATE wide-field instruments, there are ongoing activities to develop a narrow-field wide-band spectrograph (NINJA) together with a Laser Tomography AO system (ULTIMATE-START) utilizing the Adaptive Secondary Mirror and the Laser Guide Star Facility being developed for the GLAO system. In this presentation, an overview of the ULTIMATE-SUBARU instruments, their current status, and future prospects will be presented.
The discovery of a fair sample of Earth-analogues (Earth 2.0’s), i.e. rocky, Earth-mass exoplanets orbiting a Solar-type star in that host star’s habitable zone, and a subsequent search of evidence of bioactivity on those Earth 2.0’s by the detection of biogenically produced molecules in those exoplanetary atmospheres, are two of the most urgent observational programs in astrophysics and science in general. To identify an Earth 2.0, it is necessary to measure the reflex motion radial velocity amplitude of the host star at the 10 cm/sec level, a precision considerably below that which is currently achievable with existing instruments. The follow-on project to search for the biomarkers in an Earth 2.0’s atmosphere may require an effective planet/star contrast of 10-10, again well below the currently achievable level. In this paper, we discuss technical innovations in the implementation of the GMT-Consortium Large Earth Finder (G-CLEF) spectrograph that will enable these observational objectives. We discuss plans to operate G-CLEF at the Magellan Clay telescope with the MagAO-X adaptive optics system and subsequently with GMagAO-X at the Giant Magellan Telescope (GMT).
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS covers 1.3-degree diameter field with 2386 fibers to complement the imaging capability of Hyper Suprime Cam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners with science fibers are located. The PFI was delivered to the Subaru telescope in June 2021. Consequently, several tests and engineering runs were carried out to calibrate the PFI and also verify the performance of the PFI with the telescope. Some improvements were made including the focus adjustment of the acquisition and guiding cameras to match which of the science fibers, and the calibration of the AG camera positions and the flux calibrations. The key performance for PFI is so called the convergence rate, i.e. the successful rate of the Cobra positioners to reach the target positions within the assigned time. The convergence process includes iterations between movements of Cobra positioners and imaging of the metrology camera system for measuring the fiber positions. Through commissioning runs, we accumulated enough data to analyze the possible factors that affect the convergence rate such as the calibration accuracy for the distortion of the wide field correctors, the thresholds to stop the positioner movement, the exposure time for the metrology camera and the dome seeing, etc... With these efforts, several improvements have been implemented to enhance the performance of the positioners and determine the optimal iteration number. The overall convergence time has also been reduced substantially. We will report the analysis and improvement done in this paper.
The Mid-infrared ELT Imager and Spectrograph (METIS) is one of the first light instruments for the Extremely Large Telescope (ELT) and will cover the thermal- and mid-infrared (3–13 μm). With the single conjugate adaptive optics (SCAO) system, it will enable high contrast imaging and integral field unit (IFU) spectroscopy (R ~ 100 000) at the diffraction limit of the ELT. Inside the METIS cryostat, it has a modular design and is composed of the common fore optics (CFO), the imager (IMG), the SCAO, and the L and M band integral field spectrograph (LMS). The components are cooled down to around 60K, or lower for the detectors, during the operation to reduce the background. In the CFO of METIS, four wheels are inserted in the optical path including the atmospheric dispersion corrector (ADC) wheel, the pupil plane one (PP1) wheel, the focal plane two (FP2) wheel and the LMS pickoff wheel. The PP1 wheel and the ADC wheel are located near the first pupil plane while the other two wheels are at the second focal plane. These wheels accommodate the optics, slits, masks and filters for various operation modes of METIS. In each wheel, common cartridges are designed to hold the optical elements to facilitate an easy exchange between them. High positioning repeatability is required for some of the optics. We will report the design and the initial integration and tests of the wheels in this paper.
SCUBA-2/POL-2 has been the most productive instrument at JCMT since it’s fully commissioned in 2011 September, and it’s constantly oversubscribed during the call-for-proposals by a factor of 3 to 5. The proposed new 850μm instrument will feature 7272 state-of-the-art Microwave Kinetic Inductance Detectors (MKIDs) operated below 100 mK, fully utilizing the JCMT’s 12 arcmin Field of View (FoV), thus have all the capabilities of SCUBA-2 at 850 μm, yet will map an order of magnitude faster. The new instrument will be incorporated with intrinsic polarization measurement capability which is 3636 pixels. Mapping the 850 μm polarization will be improved by a factor of at least 20.
ULTIMATE-Subaru is a next facility instrumentation program of the Subaru Telescope. The goal of this project is to extend the wide-field capability of the Subaru to near-infrared (NIR), by developing a wide-field ground-layer adaptive optics (GLAO) system and wide-field NIR instruments. The GLAO system will uniformly improve the image quality up to 20-arcmin field of view in diameter by correcting for the ground-layer turbulence. The expected image quality after the GLAO correction is FWHM~0".2 in K-band under moderate seeing conditions. In this presentation, we present preliminary design overview of the GLAO system at the Cassegrain focus, which consist of an Adaptive Secondary Mirror, NGS and LGS wavefront sensor system, a laser guide star facility, and control system. We also present the prototyping activities to validate the selected design of the GLAO system.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru’s prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degrees diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners and fiducial fibers are located. In addition, the acquisition and guiding cameras (AGCs), the cable wrapper, the fiducial fiber illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC’s Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. The assembly, integration and verification of PFI was completed in 2021. The performance of PFI meets the requirements and it was delivered to Subaru telescope in June 2021. Consequently, various tests and engineering runs were carried out to calibrate the PFI and verify the performance of the PFI with the telescope.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is a very wide- field, massively multiplexed, and optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed in the 1.3 degree-diameter field of view. The spectrograph system has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously deliver spectra from 380nm to 1260nm in one exposure. The instrumentation has been conducted by the international collaboration managed by the project office hosted by Kavli IPMU. The team is actively integrating and testing the hardware and software of the subsystems some of which such as Metrology Camera System, the first Spectrograph Module, and the first on-telescope fiber cable have been delivered to the Subaru telescope observatory at the summit of Maunakea since 2018. The development is progressing in order to start on-sky engineering observation in 2021, and science operation in 2023. In parallel, the collaboration is trying to timely develop a plan of large-sky survey observation to be proposed and conducted in the framework of Subaru Strategic Program (SSP). This article gives an overview of the recent progress, current status and future perspectives of the instrumentation and scientific operation.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover a 1.3 degree diameter field with 2394 fibers to complement the imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final positioning accuracy between the fibers and observing targets of PFS is required to be less than 10 µ m. The metrology camera system (MCS) serves as the optical encoder of the fiber positioners for configuring of fibers. The MCS locates at the Cassegrain focus of the Subaru telescope to cover the whole focal plane with one 50M pixel CMOS sensor. The information from MCS will be fed into the fiber positioner control system for closed loop control. The MCS was delivered to Subaru Observatory in Apr. 2018 and it had two engineering runs in Oct. 2018 and Aug. 2019. The 1st engineering run concluded that the original mirror supports need to be improved to provide better image quality. The newly designed mirror supports were installed before the 2nd engineering run. The 2nd engineering run result shows that the MCS overall position accuracy is better than 4μm and the image processing time is less than 4 seconds. The MCS is ready for the system integration with other PFS components.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degrees diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners and fiducial fibers are located. In addition, the acquisition and guiding cameras (AGCs), the cable wrapper, the fiducial fiber illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC’s Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. The delivery of PFI components started in 2017. After the verification of these components, the mechanical structure of the PFI is fully assembled in early 2019 and all Cobra positioners are integrated in summer 2020. A temperature controlled chamber with precise x-y scanner was setup for the verification of the fiber positioners. The testing of the target convergence performance of Cobra positioners is now in progress.
Results of a conceptual design study of ULTAIMTE-Wide Field Imager (WFI) is presented. ULTIMATE-WFI is a near-infrared wide-field imager for the ground-layer adaptive optics system of the Subaru telescope (ULTIMATESubaru) which realizes a 0. 002 seeing size over 200diameter at the Cassegrain focus utilizing a deformable 2ndry mirror. WFI has a 15. 07×15. 07 FoV with a wavelength coverage of 0.9–2.5µm. The FoV is covered by four identical optics, each having a square field lens with 226mm on a side. Its effective FoV is 7. 02 on a side, and is covered by a HAWAII-4RG array detector with a pixel scale of 0. 0011/pix. Effective FoV will be 14. 04×14. 04 or 2070 in total. Spot sizes at a detector plane are less than 0. 001 over the wavelength coverage. Due to the large FoV, vignetting by the telescope structure occurs and an additional cold stop is necessary to block their thermal emission, which causes ~80% vignetting at the edge of the FoV. All the optics are contained in a cylindrical structure to be installed on the Cassegrain focus of the telescope, and kept under cryogenic temperature except for the field lenses. Gravitational deformation will be smaller than 1mm, and may have negligible impact on the final image quality.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~ 1.6-2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project recently started undertaking the commissioning process of a subsystem at the Subaru Telescope side, with the integration and test processes of the other subsystems ongoing in parallel. We are aiming to start engineering night-sky operations in 2019, and observations for scientific use in 2021. This article gives an overview of the instrument, current project status and future paths forward.
We have recently commissioned a novel infrared (0:9-1:7 μm) integral field spectrograph (IFS) called the Wide Integral Field Infrared Spectrograph (WIFIS). WIFIS is a unique instrument that offers a very large field-of-view (5000 x 2000) on the 2.3-meter Bok telescope at Kitt Peak, USA for seeing-limited observations at moderate spectral resolving power. The measured spatial sampling scale is ~ 1 x 1" and its spectral resolving power is R ~ 2; 500 and 3; 000 in the zJ (0:9 - 1:35 μm) and Hshort (1:5 - 1:7 μm) modes, respectively. WIFIS's corresponding etendue is larger than existing near-infrared (NIR) IFSes, which are mostly designed to work with adaptive optics systems and therefore have very narrow fields. For this reason, this instrument is specifically suited for studying very extended objects in the near-infrared such as supernovae remnants, galactic star forming regions, and nearby galaxies, which are not easily accessible by other NIR IFSes. This enables scientific programs that were not originally possible, such as detailed surveys of a large number of nearby galaxies or a full accounting of nucleosynthetic yields of Milky Way supernova remnants. WIFIS is also designed to be easily adaptable to be used with larger telescopes. In this paper, we report on the overall performance characteristics of the instrument, which were measured during our commissioning runs in the second half of 2017. We present measurements of spectral resolving power, image quality, instrumental background, and overall efficiency and sensitivity of WIFIS and compare them with our design expectations. Finally, we present a few example observations that demonstrate WIFIS's full capability to carry out infrared imaging spectroscopy of extended objects, which is enabled by our custom data reduction pipeline.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover a 1.3 degree diameter field with 2394 fibers to complement the imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final positioning accuracy between the fibers and observing targets of PFS is required to be less than 10 μm. The metrology camera system (MCS) serves as the optical encoder of the fiber positioners for the configuring of fibers. MCS provides the fiber positions within a 5 microns error over the 45 cm focal plane. The information from MCS will be fed into the fiber positioner control system for the closed loop control. MCS locates at the Cassegrain focus of Subaru telescope to cover the whole focal plan with one 50M pixel Canon CMOS camera. It is a 380 mm aperture Schmidt type telescope which generates uniform spot size around 10 µm FWHM across the field for reasonable sampling of the point spreading function. An achromatic lens set is designed to remove the possible chromatic error due to the variation of the LED wavelength. Carbon fiber tubes are used to provide stable structure over the operation conditions without focus adjustments. The CMOS sensor can be read in 0.8 s to reduce the overhead for the fiber configuration. The positions of all fibers can be obtained within 0.5 s after the readout of the frame. This enables the overall fiber configuration to be less than 2 minutes. MCS is installed inside a standard Subaru Cassgrain Box. All components generate heat are located inside a glycol cooled cabinet to reduce the possible image motion due to the heat. The integration of MCS started from fall 2017 and it was delivered to Subaru in April 2018. In this report, the performance of MCS after the integration and verification process in ASIAA and the performance after the delivery to Subaru telescope are presented.
We present the optomechanical design and development of the Wide Integral Field Infrared Spectrograph (WIFIS). WIFIS will provide an unrivalled integral field size of 20”×50” for a near-infrared (0.9-1.7 μm) integral-field spectrograph at the 2.3-meter Steward Bok telescope. Its main optomechanical system consists of two assemblies: a room-temperature bench housing the majority of the optical components and a cryostat for a field-flattening lens, thermal blocking filter, and detector. Two additional optical subsystems will provide calibration functionality, telescope guiding, and off-axis optical imaging. WIFIS will be a highly competitive instrument for seeing-limited astronomical investigations of the dynamics and chemistry of extended objects in the near-infrared wavebands. WIFIS is expected to be commissioned during the end of 2016 with scientific operations beginning in 2017.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover a 1.3 degree diameter field with 2394 fibers to complement the imaging capabilities of Hyper SuprimeCam. To retain high throughput, the final positioning accuracy between the fibers and observing targets of PFS is required to be less than 10 microns. The metrology camera system (MCS) serves as the optical encoder of the fiber motors for the configuring of fibers. MCS provides the fiber positions within a 5 microns error over the 45 cm focal plane. The information from MCS will be fed into the fiber positioner control system for the closed loop control. MCS will be located at the Cassegrain focus of Subaru telescope in order to cover the whole focal plane with one 50M pixel Canon CMOS camera. It is a 380mm Schmidt type telescope which generates a uniform spot size with a ~10 micron FWHM across the field for reasonable sampling of the point spread function. Carbon fiber tubes are used to provide a stable structure over the operating conditions without focus adjustments. The CMOS sensor can be read in 0.8s to reduce the overhead for the fiber configuration. The positions of all fibers can be obtained within 0.5s after the readout of the frame. This enables the overall fiber configuration to be less than 2 minutes. MCS will be installed inside a standard Subaru Cassgrain Box. All components that generate heat are located inside a glycol cooled cabinet to reduce the possible image motion due to heat. The optics and camera for MCS have been delivered and tested. The mechanical parts and supporting structure are ready as of spring 2016. The integration of MCS will start in the summer of 2016. In this report, the performance of the MCS components, the alignment and testing procedure as well as the status of the PFS MCS will be presented.
PFS (Prime Focus Spectrograph), a next generation facility instrument on the 8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed, optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed over the 1.3 deg field of view. The spectrograph has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure at a resolution of ~1.6 - 2.7Å. An international collaboration is developing this instrument under the initiative of Kavli IPMU. The project is now going into the construction phase aiming at undertaking system integration in 2017-2018 and subsequently carrying out engineering operations in 2018-2019. This article gives an overview of the instrument, current project status and future paths forward.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degree diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners are located. In addition, the acquisition and guiding cameras (AGCs), the optical fiber positioner system, the cable wrapper, the fiducial fibers, illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC’s Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. In this report, the latest status of PFI development will be given including the performance of PFI components, the setup and performance of the integration and testing equipment.
The Prime Focus Spectrograph (PFS) is an optical/near-infrared multifiber spectrograph with 2394 science fibers distributed across a 1.3-deg diameter field of view at the Subaru 8.2-m telescope. The wide wavelength coverage from 0.38 μm to 1.26 μm, with a resolving power of 3000, simultaneously strengthens its ability to target three main survey programs: cosmology, galactic archaeology and galaxy/AGN evolution. A medium resolution mode with a resolving power of 5000 for 0.71 μm to 0.89 μm will also be available by simply exchanging dispersers. We highlight some of the technological aspects of the design. To transform the telescope focal ratio, a broad-band coated microlens is glued to each fiber tip. A higher transmission fiber is selected for the longest part of the cable system, optimizing overall throughput; a fiber with low focal ratio degradation is selected for the fiber-positioner and fiber-slit components, minimizing the effects of fiber movements and fiber bending. Fiber positioning will be performed by a positioner consisting of two stages of piezo-electric rotary motors. The positions of these motors are measured by taking an image of artificially back-illuminated fibers with the metrology camera located in the Cassegrain container; the fibers are placed in the proper location by iteratively measuring and then adjusting the positions of the motors. Target light reaches one of the four identical fast-Schmidt spectrograph modules, each with three arms. The PFS project has passed several project-wide design reviews and is now in the construction phase.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph design for the prime focus
of the 8.2m Subaru telescope. PFS will cover 1.3 degree diameter field with 2394 fibers to complement the imaging
capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the
interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber
positioners are located. In addition, the acquisition and guiding (AG) cameras, the optical fiber positioner system, the
cable wrapper, the fiducial fibers, illuminator, and viewer, the field element, and the telemetry system are located inside
the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match
those of the HSC’s Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations
within the required accuracy.
The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime
focus of the 8.2m Subaru telescope. The metrology camera system of PFS serves as the optical encoder of the COBRA
fiber motors for the configuring of fibers. The 380mm diameter aperture metrology camera will locate at the Cassegrain
focus of Subaru telescope to cover the whole focal plane with one 50M pixel Canon CMOS sensor. The metrology
camera is designed to provide the fiber position information within 5μm error over the 45cm focal plane. The positions
of all fibers can be obtained within 1s after the exposure is finished. This enables the overall fiber configuration to be
less than 2 minutes.
The Prime Focus Spectrograph (PFS) is an optical/near-infrared multi-fiber spectrograph with 2394 science fibers, which
are distributed in 1.3 degree diameter field of view at Subaru 8.2-meter telescope. The simultaneous wide wavelength
coverage from 0.38 μm to 1.26 μm, with the resolving power of 3000, strengthens its ability to target three main survey
programs: cosmology, Galactic archaeology, and galaxy/AGN evolution. A medium resolution mode with resolving
power of 5000 for 0.71 μm to 0.89 μm also will be available by simply exchanging dispersers. PFS takes the role for the
spectroscopic part of the Subaru Measurement of Images and Redshifts (SuMIRe) project, while Hyper Suprime-Cam
(HSC) works on the imaging part. HSC’s excellent image qualities have proven the high quality of the Wide Field
Corrector (WFC), which PFS shares with HSC. The PFS collaboration has succeeded in the project Preliminary Design
Review and is now in a phase of subsystem Critical Design Reviews and construction.
To transform the telescope plus WFC focal ratio, a 3-mm thick broad-band coated microlens is glued to each fiber tip.
The microlenses are molded glass, providing uniform lens dimensions and a variety of refractive-index selection. After
successful production of mechanical and optical samples, mass production is now complete. Following careful
investigations including Focal Ratio Degradation (FRD) measurements, a higher transmission fiber is selected for the
longest part of cable system, while one with a better FRD performance is selected for the fiber-positioner and fiber-slit
components, given the more frequent fiber movements and tightly curved structure. Each Fiber positioner consists of two
stages of piezo-electric rotary motors. Its engineering model has been produced and tested. After evaluating the statistics
of positioning accuracies, collision avoidance software, and interferences (if any) within/between electronics boards,
mass production will commence. Fiber positioning will be performed iteratively by taking an image of artificially back-illuminated
fibers with the Metrology camera located in the Cassegrain container. The camera is carefully designed so
that fiber position measurements are unaffected by small amounts of high special-frequency inaccuracies in WFC lens
surface shapes.
Target light carried through the fiber system reaches one of four identical fast-Schmidt spectrograph modules, each with
three arms. All optical glass blanks are now being polished. Prototype VPH gratings have been optically tested. CCD
production is complete, with standard fully-depleted CCDs for red arms and more-challenging thinner fully-depleted
CCDs with blue-optimized coating for blue arms. The active damping system against cooler vibration has been proven to
work as predicted, and spectrographs have been designed to avoid small possible residual resonances.
We present the current results from the development of a wide integral field infrared spectrograph (WIFIS). WIFIS offers an unprecedented combination of etendue and spectral resolving power for seeing-limited, integral field observations in the 0.9 - 1.8 μm range and is most sensitive in the 0.9 - 1.35 μ,m range. Its optical design consists of front-end re-imaging optics, an all-reflective image slicer-type, integral field unit (IFU) called FISICA, and a long-slit grating spectrograph back-end that is coupled with a HAWAII 2RG focal plane array. The full wavelength range is achieved by selecting between two different gratings. By virtue of its re-imaging optics, the spectrograph is quite versatile and can be used at multiple telescopes. The size of its field-of-view is unrivalled by other similar spectrographs, offering a 4.511x 1211 integral field at a 10-meter class telescope (or
2011 x 5011 at a 2.3-meter telescope). The use of WIFIS will be crucial in astronomical problems which require
wide-field, two-dimensional spectroscopy such as the study of merging galaxies at moderate redshift and nearby star/planet-forming regions and supernova remnants. We discuss the final optical design of WIFIS, and its predicted on-sky performance on two reference telescope platforms: the 2.3-m Steward Bok telescope and the
10.4-m Gran Telescopio Canarias. We also present the results from our laboratory characterization of FISICA.
IFU properties such as magnification, field-mapping, and slit width along the entire slit length were measured by our tests. The construction and testing of WIFIS is expected to be completed by early 2013. We plan to commission the instrument at the 2.3-m Steward Bok telescope at Kitt Peak, USA in Spring 2013.
We present the optical design of the Wide Integral Field Infrared Spectrograph (WIFIS) which provides an unprecedented
combination of the integral field size and the spectral resolving power in the near-infrared wavebands.
The integral field size and spectral resolving power of WIFIS are ~ 5× 12on a 10-m telescope (or equivalently
13× 30on a 4-m telescope) and ~ 5300, respectively. Therefore, the affordable etendue of WIFIS is larger
than any other near-infrared integral field spectrographs while its spectral resolving power is comparable to the
highest value provided by other spectrographs. WIFIS optical system comprises an Offner relay-based pre-slit
unit, an image slicer for integral-field unit, a collimator, diffraction gratings, and a spectrograph camera. For the
integral field unit, WIFIS uses the Florida Image Slicer for Infrared Cosmological and Astrophysics which is a set
of 3 monolithic mirror arrays housing 22 image slicers. The collimator system consists of one off-axis parabola
and two lenses, while WIFIS relies on 3 different gratings to cover the entire JHK bands. The spectrograph
camera uses 6 lenses of CaF2 and SFTM16, delivering the f/3 final beam onto a Hawaii II RG 2K × 2K detector
array. WIFIS will be an ideal instrument to study the dynamics and chemistry of extended objects.
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