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.
Hyper Suprime-Cam (HSC) is the optical and near-infrared wide-field camera equipped on the Subaru Telescope. Its huge field of view (1.5 degree diameter) with 104 CCDs and the large mirror (8.2m) of the telescope will make us to study the Universe more efficiently. The analysis pipeline for HSC data produces processed images, and object catalogs of each CCD and stacked images. For survey in next 5 years, the number of rows in the object catalog table will reach to at least 5 x 10<sup>9</sup>. We show the outline of the database systems of HSC data to store those huge data.
We describe a data providing system for Hyper Suprime-Cam (HSC) of Subaru Telescope. The data providing system provides HSC data including images and catalogs of celestial objects derived from them to individual co-investigators of the Subaru Strategic Survey Program with HSC through a website. Users can select the data that they need by using its graphical user interface or writing a query in SQL and download the selected images or the catalogs.
Hyper Suprime-Cam (HSC) is an 870 Mega pixel prime focus camera for the 8.2 m Subaru telescope. The wide field corrector delivers sharp image of 0.25 arc-sec FWHM in r-band over the entire 1.5 degree (in diameter) field of view. The collimation of the camera with respect to the optical axis of the primary mirror is realized by hexapod actuators whose mechanical accuracy is few microns. As a result, we expect to have seeing limited image most of the time. Expected median seeing is 0.67 arc-sec FWHM in i-band. The sensor is a p-ch fully depleted CCD of 200 micron thickness (2048 x 4096 15 μm square pixel) and we employ 116 of them to pave the 50 cm focal plane. Minimum interval between exposures is roughly 30 seconds including reading out arrays, transferring data to the control computer and saving them to the hard drive. HSC uniquely features the combination of large primary mirror, wide field of view, sharp image and high sensitivity especially in red. This enables accurate shape measurement of faint galaxies which is critical for planned weak lensing survey to probe the nature of dark energy. The system is being assembled now and will see the first light in August 2012.
Hyper Suprime-Cam (HSC) employs 116 pieces of 2k×4k fully-depleted CCD with a total of 464 signal outputs to cover
the 1.5 degrees diameter field of view. The readout electronics was designed to achieve ~5 e of the readout noise and
150000 e of the fullwell capacity with 20 seconds readout time. Although the image size exceeds 2G Bytes, the readout
electronics supports the 10 seconds readout time for the entire CCDs continuously. All of the readout electronics and the
CCDs have already been installed in the camera dewar. The camera has been built with equipment such as coolers and an
ion pump. We report the readout performance of all channels of the electronics extracted from the recent test data.
We introduce the detail of the control system of Hyper Suprime-Cam (HSC) and its performance. Although it
has almost 10 times as many CCDs (104) as existing camera (Suprime-Cam), it is controlled by the common
user interface, the Subaru Observation Software System (SOSS) with the Gen2 implementation through the
HSC local controller (OBCP). If we adopt parallel programming, the read-out time should be within 25 seconds
including 18.6 seconds of readout time which is comparable to the current Suprime-Cam.
Hyper Suprime-Cam (HSC) is the next generation wide-field imager for the prime focus of Subaru Telescope,
which is scheduled to receive its first light in 2011. Combined with a newly built wide-field corrector, HSC
covers 1.5 degree diameter field of view with 116 fully-depleted CCDs. In this presentation, we summarize the
details of the camera design: the wide-field corrector, the prime focus unit, the CCD dewar and the peripheral
devices. The wide-field corrector consists of 5 lenses with lateral shift type doublet ADC element. The novel
design guarantees the excellent image quality (D<sub>80</sub> <0".3) over the field of view. On the focal plane, 116 CCDs
are tiled on the cold plate which is made of Silicon Carbide (SiC) and cooled down to -100 degrees by two pulse
tube coolers. The system is supported by the prime focus unit which provides a precise motion of the system to
align the wide-field corrector and the CCD dewar to the optical axis of the telescope.
We report an analysis framework developed for the Hyper Suprime-Cam. The framework is featured by distributed
parallel execution and a Python interface. With the Python interface, it collaborates with the LSST
application framework. Thus we have developed a test pipeline with both the frameworks, and tested its parallelization
We develop a prototype of data analysis system for the wide-field camera Hyper Suprime-Cam (HSC) at Subaru Telescope. The current prototype is optimized for data of the current Subaru prime-focus camera Suprime-Cam, which is a precursor instrument of HSC, to study the on-site data evaluation for wide-field imaging.
The system conducts realtime data evaluation for every data frame obtaining statistical information including seeing, sky-background level, astrometric solution, and photometric zeropoint when available.
Variations in time of the derived values are shown on a web-based status monitor. The on-demand analysis such as mosaicing analysis is performed using the data evaluation results.
This system consists of analysis pipelines responsible for data processing, and the analysis organizing software for controlling analysis tasks and data flow and the database.
The XML-based database maintains all the analysis results and analysis histories. Improvement of the analysis speed by parallel data processing is achieved with the aid of the organizing software.
This system has started operation in general observations since March 2010, and will be extended to process the 104 CCD's of HSC.
The system may be used for observing support and also possible to apply to another imaging-mode instruments in the future.
Hyper Suprime-Cam (HSC) employs 116 of 2k×4k CCDs with 464 signal outputs in total. The image size
exceeds 2 GBytes, and the data can be readout every 10 seconds which results in the data rate of 210 Mbytes /
sec. The data is digitized to 16-bit. The readout noise of the electronics at the readout time of 20 seconds is
~0.9 ADU, and the one with CCD is ~1.5 ADU which corresponds to ~4.5 e. The linearity error fits within ±
0.5 % up to 150,000 e. The CCD readout electronics for HSC was newly developed based on the electronics
for Suprime-Cam. The frontend electronics (FEE) is placed in the vacuum dewar, and the backend electronics
(BEE) is mounted on the outside of the dewar on the prime focus unit. The FEE boards were designed to
minimize the outgas and to maximize the heat transfer efficiency to keep the vacuum of the dewar. The BEE
boards were designed to be simple and small as long as to achieve the readout time within 10 seconds. The
production of the system has been finished, and the full set of the boards are being tested with several CCDs
installed in the HSC dewar. We will show the system design, performance, and the current status of the
A dichroic mirror/filter can divide light into two different wavelength bands by the principle of interference. We proposed to use more than a dozen of these mirrors, and make a simultaneous imager in many color bands. This also enables us to make a powerful spectrograph which uses many CCDs. We here report the first light of UT 15-band Dichroic-Mirror Camera. We successfully obtained the first light at the Cassegrain focus of the 1.5-m Kanata telescope in May 2007. We also carried out the second observing run in March 2008. Our instrument covers a wide wavelength range (390-930nm), and the field of view is about 4.5 arcmin in diameter with 0.27arcsec/pixel. Image quality was limited by seeing (~1.2 arcsec at best). We describe basic design, characteristics, and performance of our instrument as well as early observational results. Future prospect of dichroic mirrors instruments will also be briefly discussed.
We report our activity on development of data analysis system dedicated for the Hyper Suprime-Cam (HSC),
which is a future wide-field camera at Subaru Telescope. The data analysis system (HSC-ANA) is intended for
the following achievements: (1) automated processing of an unprecedentedly huge amount of data frames without
frequent human interactions to achieve required depth and area of the key survey projects (2) immediate release
of best-effort object catalogs together with calibration information to user communities to maximize scientific
outputs. The system also enables general users to efficiently use archive data by providing appropriate meta data
describing data quality. We start with constructing a prototype data analysis system which involves minimal
functions to process data for the current prime-focus camera (Suprime-Cam). The prototype system is developed
based on combination of newly developed and existing software packages for imaging data and the framework
middleware which communicates with databases. This system is planned to help observers to perform their
observations with Suprime-Cam. Once the prototype system is evaluated, it will be scaled up to the full HSCANA
Hyper Suprime-Cam is planned to employ about 120 2k×4k fully-depleted CCDs with 4 signal outputs for each. The
data size of an image becomes larger than 2Gbytes. All of the CCDs are designed to be readout parallel within 20
seconds, and the readout noise is expected to be 5e. The frontend electronics will be mounted in a vacuumed cryostat,
and connected to the backend electronics mounted on the outside of the cryostat. The frontend electronics includes entire
analog circuits for CCD including CCD drivers, preamplifiers and ADC. The backend electronics consists of newly
developed gigabit Ethernet modules combined with 2Gbytes memory modules, and several supporting boards. We will
present the current status of the CCD readout electronics developments for HSC.
We present methodology of the autoguider (AG) and Shack-Hartmann (SH) sensing systems which will be used for a wide-field camera, Hyper Suprime-Cam (HSC), on the prime focus of the Subaru 8.2-m telescope. For both systems, stellar images are formed on the HSC science CCDs. Although light from AG stars must pass
through bandpass filters, we can obtain enough photons for AG stars brighter than m<sub>AB</sub> < 14 mag in any bandpass filter assumed in order to achieve accurate autoguiding. Spatial number density of such bright stars from the SDSS database requires an area
of about two 2k×4k CCDs for AG stars. The optics of SH system except for the imaging CCDs is located within the HSC filter unit.
We summarize the design of the camera dewar for Hyper Suprime-Cam (HSC) which is the next generation prime
focus camera for the Subaru Telescope. The camera dewar consists of six main components; base flange, focal
plane assembly, window assembly, wall assembly, front-end electronics asembly and back assembly. It is about 700
mm in diameter and 500 mm in height, accommodating 116 2k×4k full depletion type CCDs inside. The CCD
packages, whose heights are accurately controlled (P-V ~ 25μm), are installed on a silicon-carbide cold plate of 10 μm
flatness to ensure that the surface of CCDs is flat within the focal depth of the wide-field corrector (~ 34μm).
The cold plate is supported rigidly and thermally isolated by support posts which are made of Zirconia. We
carried out the deformation analysis and the thermal analysis of the dewar based on the finite-element analysis,
and demonstrate that the design is feasible. We also show the assembly sequence of the dewar.
We summarize the optical design of the wide-field corrector for HyperSuprime which is being considered as a next generation prime focus camera for Subaru Telescope. Two optical designs are investigated under several design constraints such as image quality, field curvature, focal length, etc. The corrector with 2 degree field of view attains good image quality at the wavelength between 600 nm and 1100 nm although the first lens is large (1.2 m in diameter) and three aspherical surfaces are required. The image quality for shorter wavelength than 600 nm is fair. The incident light blocked at the edge of the field is only 20% and the transmission is more than 80% if the multi-layer coating applied for the current Subaru prime focus corrector is available. The corrector with 1.5 degree field of view is designed as a smaller version of 2 degree corrector. The properties and performance of 1.5 degree corrector resemble those of 2 degree corrector, but 1.5 degree corrector has a merit that the focal plane is flat. The availability of large fused-silica blank up to about 200 kg is promising.
HyperSuprime is a next generation wide field camera proposed for the 8.3 m Subaru Telescope. The targeted field of view is larger than 1.5 deg in diameter, which will give us roughly 10 times increase of the survey speed compared with the existing prime focus camera (Suprime-Cam). An overview of the current status of the feasibility study is given.
We summarize the design and the specification of a next generation instrument for Subaru Telescope: a very wide-field (2°φ) CCD camera which we name HyperSuprime. The latest design of the corrector ensures 80% encircled energy diameter of 0".3 from 600 nm to 1100 nm over the 2°φ field of view. The size of the focal plane is 612 mm in diameter and covered by about 170 four side buttable 2kx4k CCDs. Fully depleted CCD which is now being developed is the primary candidate for HyperSuprime. The readout electronics is connected behind the CCD and this CCD package is screwed to the cold plate with three positioning pins. The large entrance window of the dewar is supported with additional ribs so that the dewar is evacuated and CCDs are cooled down to about -80°C. HyperSuprime equips with a filter exchanger which can accommodate four large mosaicked filters and a roll-type shutter.
The Suprime-Cam is a CCD camera which is attached to the prime focus of the Subaru Telescope. Ten MIT/LL CCDs are tiled with small gaps to realize large field of view (34' x 27') with 0.2 arcsec sampling. This makes the Suprime-Cam very powerful and unique instrument
among 8-10m class telescopes. We present basic design, key techniques, current status and performance of the Suprime-Cam. We also mention ongoing survey programs with the Suprime-Cam,
followed by future upgrade plans of the camera.
The Subaru telescope has an excellent performance of wide field of view at the prime focus. A big area of 30 feet times 24 feet is observable at a time with the prime focus camera. Making the best use of the wide view, we are constructing narrowband (NB) filter system consisting of 20 bands. This system covers the wavelengths between 4,000 angstrom and 10,000 angstrom. The band width (BW) varies form 200 angstrom to 400 angstrom depending on the center wavelength (CW). The resolving power of the system is 23. Each filter has a big dimension of 205mm times 170mm and excellent uniformities on CW, BW and peak transmittance. Employing this filter system, spectroscopy for all objects recorded in fields of view is possible at the wavelength resolution of R23. The limiting magnitude would reach 27AB in reasonable observation time even at long wavelength bands. Such deep NB imaging spectroscopic survey should provide huge catalogue on cosmological objects. Especially, photometric redshift analyses with higher spectral resolution of R23 than ordinary broadband system of R approximately equals 4, will revolutionarily develop studies on formation and evolution of galaxies together with search for large scale structures at high redshift, based on enormous statistics, for example, 10<SUP>4</SUP> or more galaxies at high redshift of z > 3. Also, a lot of objects having strong emission lines as QSO/AGNs and Ly(alpha) or more galaxies will be discovered, because NB filter is strong in detection of emission line. The use of NB filter is strong in detection of emission line. The use of NB filter system in survey observations is surely quite conservative in concept and time consuming in general. However, combining this method with the wide field of view provided in the largest class telescope, new window to the universe is going to open.
We describe the design and performance of a dichroic-mirror camera (DMC) which can take 15 narrow-band images simultaneously. We separate the wavelength range of 390 - 950 nm into 15 narrow bands with 14 dichroic mirrors. The detector of DMC is a mosaic CCD camera which has 15 CCDs (TI TC-215). When we put DMC to the MAGNUM 2-m (F/9) telescope being built at Haleakala, Hawaii, the field of view becomes about 4.5 arcmin in diameter. The design of optics shows that we can get an image size of about 0.13 arcsec r.m.s. or better (without atmosphere), though we use only two different kind of lenses (the camera lens and the collimator lens). The system throughput of DMC as a function of wavelength is quantitatively estimated. Simulations using spectra of galaxies ad Qnd QSOs show that DMC can get a signal-to-noise (S/N) of approximately greater than 5/band/object for galaxies (I<SUB>AB</SUB> equals 22) and QSOs (I<SUB>AB</SUB> equals 23) in the images of 30 min - 1 hour exposure taken with a 2-m telescope. Future prospects for possible enhancements and applications of dichroic-mirror system are also discussed. Having a DMC with resolution of about 30 would be very adequate for high redshift supernovae search. To get higher resolution, DMC combined with Fabry-Perot's is an interesting possibility.