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.
Subaru Telescope has recently replaced most equipment of Subaru Telescope Network II with the new equipment which
includes 124TB of RAID system for data archive. Switching the data storage from tape to RAID enables users to access
the data faster. The STN-III dropped some important components of STN-II, such as supercomputers, development &
testing subsystem for Subaru Observation Control System, or data processing subsystem. On the other hand, we invested
more computers to the remote operation system. Thanks to IT innovations, our LAN as well as the network between Hilo
and summit were upgraded to gigabit network at the similar or even reduced cost from the previous system. As the result
of the redesigning of the computer system by more focusing on the observatory operation, we greatly reduced the total
cost for computer rental, purchase and maintenance.
We've implemented remote observing function to Subaru telescope Observation Software system (SOSs). Subaru telescope has three observing-sites, i.e., a telescope local-site and two remote observing-sites, Hilo base facility in Hawaii and Mitaka NAOJ headquarter in Japan. Our remote observing system is designed to allow operations not only from one of three observing-sites, but also from more than two sites concurrently or simultaneously. Considering allowance for delay in observing operations and a bandwidth of the network between the telescope-site and the remote observing-sites, three types of interfaces (protocols) have been implemented. In the remote observing mode, we use socket interface for the command and the status communication, vnc for ready-made applications and pop-up windows, and ftp for the actual data transfer. All images taken at the telescope-site are transferred to both of two remote observing-sites immediately after the acquisition to enable the observers' evaluation of the data. We present the current status of remote observations with Subaru telescope.
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.
We have developed and are operating an object-oriented data reduction and data analysis system, DASH ( Distributed Analysis Software Hierarchy ), for efficient data processing for SUBARU telescope. In DASH, all information for reducing a set of data is packed into an abstracted object, named as ``Hierarchy''. It contains rules how to search calibration data, reduction procedure to the final result, and also the reduction log. With Hierarchy, DASH works as an automated reduction pipeline platform cooperated with STARS (Subaru Telescope ARchive System).
DASH is implemented on CORBA and Java technology. The portability of these technology enables us to make a subset of the system for a small stand-alone system, SASH. SASH is compatible with DASH and one can continuously reduce and analyze data between DASH and SASH.
In order to achieve an effective operation and research based on data taken by the Subaru Telescope, we installed a satellite storage and analysis system at Mitaka headquarters of Naoj, on March 2002. Data taken by instruments by Subaru Telescope located at the summit of Mauna Kea is transferred to the STN-II system at Hilo base, and satellite system at Mitaka through the OC3 dedicated network link between Hilo and Mitaka. In Japan, an academic research backbone, SuperSINET spans among various universities and institutes with 10Gbps bandwidth at most, and it is easy for astronomers from Japan to access Subaru data through high speed backbone network in Japan. Database on each site, Hilo and Mitaka, are maintained independently, however, all records and history of updating are transferred each other frequently enough to make it possible for recovery in case of any discrepancy among database. Since the round trip time of the light signal between Hawaii and Japan could not be reduced 45msec, we need a special tuning not only for the data transfer between those two node, but also for the remote control sequence.
After the starting of operation on December 1998, Subaru Telescope ARchive System(STARS) continued to store and manage the data taken at the summit of Mauna Kea,
Hawaii, and total amount of data is currently about 3 TB in amount or ~ 600,000 files. The data production rate is increasing gradually with increasing stability of telescope and instrument operation.
There were some upgrades in STARS itself after our report performed in the last SPIE meeting held in Munich on March 2000, and also were some new features developed and
established in Mitaka, Japan for mirroring all data stored in STARS. We also started the releasing the data whicv passed the proprietary terms to world wide via seperate system.
We will discuss about the concepts and current status of our distributed archive systems in detail, and its impact to scientific or enginieering return from Subaru telescope.
The first generation of STN with 150TB tape library has been utilized by Subaru telescope for the past several years of operation. We are upgrading the storage system to 600TB of capacity based on the Digital Tape Format 2 of SONY Ltd, in March 2002, so called STN-II. The engine is changed from the VPP700 of Fujitsu Ltd., twenty two vector processors are connected by a cross bar network to the cluster of PrimePower2000 of Fujitsu Ltd., which consists of 128 processors each, with 384GB of quasi-shared memory in total. Data management servers and graphical workstations are connected by the Storage Area Network technology. There are two dedicated clusters of workstations for daily development of software for the archive system, STARS, and for the platform of the data analysis pipeline, DASH. These two software components are combined into the Subaru Software Trinity, with the observation control system, SOSS. The STN-II system is the platform to support observation data flow of the Subaru Telescope with the Subaru Software Trinity. Adopting a powerful computation and fast network, a system for real time quality measurement of the observation is planned and quick feedback to the observation parameter will be possible on the system.
Subaru Quality Control Trinity consists of SOSS (Subaru Observation Software System), STARS (Subaru Telescope ARchive System), and DASH (Distributed Analysis System Hierarchy), each of which can be operated independently and also cooperatively with Observation Dataset. For the purpose of evaluating the trinity, test observations were made on June 2001 with the instrument SuprimeCam attached onto the prime focus of the Subaru Telescope. We finally confirmed that the trinity works successfully and the concept of our Observation Dataset can be applicable to the quality control purpose.
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, 104 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.
After the first light, Subaru telescope produced about 86,000 frames or 400 giga bytes data during its test observation by the end of February 2000. STARS (Subaru Telescope ARchive System) contains all data and is serving them to the observers. STARS also provides several convenient tool and information such as QLI (Quick Look Image) by the aid of QP (QLI Producer) and QLIS (QLI Server), HDI (HeaDer Information file), and machine readable (on-line) memorandum for observed data, for making users know the rough quality of the data at a glance. QLI file is a FITS file with FITS BINTABLE extension. By the combination of QP and QLIS (our code name is 'GYOJI'), users have data with various size (20 to 200 times smaller than original one) on their needs, and also many extracted information such as mean, maximum and minimum count values, profiles of extracted spectra in multi-slit spectroscopy or echelle spectroscopy data and so on in the original data browser (QLISFITS) written as JAVA2 applet. This functions will also be used for public data archive system in the future. For the convenience of the data analysis, STARS also handles and manages the 'dataset,' which is essential for preparing the necessary data including object and calibration frames used in data analysis by DASH (Distributed Analysis System Hierarchy: platform for data analysis of Subaru Telescope data). This 'dataset' is made at the summit system (SOSS: Subaru Observing Software System) which knows everything about the procedure of the observation performed, and is interpreted by DASH system. In this paper, we will describe the functions which STARS has and how STARS, DASH and SOSS are linked each other for leading the effective scientific and engineering returns.
We established the quality control sequence to realize the efficient observation and the production of homogeneous quality of the data. The flow is observation preparation, execution of the observation procedure, data acquisition, data archiving, data analysis, and feedback to the future observation sequence. They are closely connected with each other by the idea of observation data set. A science object frame would be valid after applying various calibrations to the data. Observation data set rule describes the 'relation' between these data: science frame and science frame, science frame and calibration frame, and calibration frame and calibration frame. 'Relation' means mainly the acquisition order and timing. The observation data set is an assembly of the data related by the observation data set rule. In the data analysis stage, the observation data set rule is used for collecting the data. Various number of data can be collected by modification of the observation data set rule. After evaluation of the analyzed data, we can find the proper observation data set rule. Then the new rule will be fed back to the observation preparation system as the template.
New framework of data analysis system (DASH) has been developed for the SUBARU Telescope. It is designed using object-oriented methodology and adopted a restaurant model. DASH shares the load of CPU and I/O among distributed heterogeneous computers. The distributed object environment of the system is implemented with JAVA and CORBA. DASH has been evaluated by several prototypings. DASH2000 is the latest version, which will be released as the beta version of data analysis system for the SUBARU Telescope.
We are developing a data reduction and analysis system DASH for efficient data processing of the SUBARU telescope. We adopted CORBA as a distributed object environment and Java for a user interface in the prototype of DASH. Moreover, we introduced a data reduction procedure cube as a kind of visual procedure script.