The high plateaus in west China (Tibet) may provide good candidate sites possibly for ELT projects. According to satellite weather data, we found that a certain area in Tibet shows potentiality for good astronomical observations with less cloud coverage. We have explored through west Tibet to watch its topography in summer, 2004. We reanalyze meteorological data collected by GAME-Tibet project. We have started weather monitor in two candidate sites in west China; Oma in western area of Tibet and Karasu near the western boundary of China. Monitoring observations using modern astronomical site-testing techniques such as a DIMM and an IR cloud monitor camera will be started to catch up continuous monitoring of seeing and cloud coverage.
We have a plan to install a micro-crack alert system for the primary
mirror of Subaru Telescope based on the monitoring of the acoustic
emission from any incident events. We report the results of our preliminary experiment for characterizing the acoustic properties of actual Subaru primary mirror. The attenuation of acoustic wave was confirmed to be small enough to allow detection of such events at any locations of the mirror. The position of incident events that might lead to the generation of possible micro-cracks can be identified within less than 3 cm accuracy by placing seven acoustic sensors along the circumference of the primary mirror.
More than three years have passed since Subaru Telescope started its Open Use operation. Currently, more than 60% of the total telescope time is spent for scientific observation. Firstly, we define an index to measure how the telescope is effectively used. By using the index, we review the use of the telescope since 2000. Remote observation and queue observation is a long-term goal of Subaru operation because they are believed to be more efficient way to use the telescope and available resource. Control and observation software has been designed and developed to achieve remote observation and queue observation. Currently, about 30% of the telescope time is used as remote observation. We will discuss how much remote observation has contributed to make the use of the telescope effective.
Optimization of observation sequences is a function necessary to get high efficiency and reliability of observations. We have implemented scheduling software in the Subaru Telescope observatory software system. The scheduling engine, Spike, developed at STScI is used with some modification for Subaru Telescope. Since the last report at SPIE (Munich, 2000), new functions to Spike are implemented on 1) optimized arrangement of an observation dataset, which consists of a target object and related calibrations, and 2) flexible scheduling of standard stars selected out of a standard star list, which is fed to Spike as a part of observation datasets. Observation datasets with some necessary information, prepared by an observer, are input to the scheduling tools to be converted to Spike Lisp input forms. A schedule created by Spike is inversely converted to Subaru observation commands to be executed with the observation control system. These applications are operable with Web-based display. We present an overall structure of the scheduling tools with some samples of Subaru observation commands of target datasets and a resultant schedule.
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.
This paper describes a new electromagnetic device for vibration control of a light-weighted deployable/retractable structure which consists of many small units connected with mechanical hinges. A typical example of such a structure is a solar cell paddle of an artificial satellite which is composed of many thin flexible blankets connected in series. Vibration and shape control of the paddle is not easy, because control force and energy do not transmit well between the blankets which are discretely connected by hinges with each other. The new device consists of a permanent magnet glued along an edge of a blanket and an electric current-conducting coil glued along an adjoining edge of another adjacent blanket. Conduction of the electric current in a magnetic field from the magnet generates an electromagnetic force on the coil. By changing the current in the coil, therefore, we may control the vibration and shape of the blankets. To confirm the effectiveness of the new device, constructing a simple paddle model consisting eight hinge- panels, we have carried out a model experiment of vibration and shape control of the paddle. In addition, a numerical simulation of vibration control of the hinge structure is performed to compare with measured data.
The Faint Object Camera and Spectrograph, FOCAS, is a Cassegrain
optical instrument of Subaru telescope. For its versatility, FOCAS
has many optical components such as grisms, filters, and polarizers.
They are inserted in the collimated beam section of 451 mm length.
For the large pupil (90 mm in diameter) and the wide field of view
(6 arcmin in diameter) of FOCAS, rigorous efforts were made in
developing, manufacturing and assembling these components.
The resultant performance of the instrument is quite stable
and is almost as high as that expected from the design values.
In the text, overall characteristics of each optical element
Faint Object Camera and Spectrograph, FOCAS, is a Cassegrain versatile optical instrument of Subaru telescope. Among various observing modes of FOCAS, the multi-object spectroscopy (MOS) requires dedicated software suite which enables accurate positioning of masks which have over fifty slitlets on faint targets over 6 arcminutes diameter field-of-view (FOV). We have been developing three kinds of software: the image processing software performing combining mosaic CCD images and optics distortion correction, mask designing program (MDP) for the slit arrangement, and pointing offset calculator (POC) for the target acquisition on slits. MDP and POC provide observers a graphical user interface (GUI) for efficient and quick mask designing and target acquisition. Our test has shown that the slit positioning accuracy on targets is about 0.2 arcsec RMS over entire FOV, and is accurate enough for typical observations with 0.4 arcsec slits or wider. We briefly describe our software as well as the pointing accuracy and the required time for the MOS target acquisition with FOCAS.
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.
Faint object camera and spectrograph, FOCAS, is a Cassegrain optical instrument of Subaru telescope. It has a capability of 6 arcmin FOV direct imaging, low resolution spectroscopy, multi-slit spectroscopy as well as polarimetry. Only the imaging mode has been available so far. The overall design, the observing functions, and the preliminary performance verifications of FOCAS will be presented.
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.
Optimization of observation sequences is a function necessary to get high efficiency and reliability of observations. We are now implementing scheduling software into the observation software system for Subaru telescope. The scheduling engine, SPIKE, developed at STScI is used with some modification for the Subaru telescope. An observation target list prepared by observers is converted to SPIKE Lisp codes. SPIKE output is inversely converted to Subaru commands to be executed with the observation software system. Real-time scheduling is planned to re-schedule observations by judging the weather and satisfaction conditions with the help of observation history. The scheduling software can be also used as support tools for observers to indicate an object good for the next observation.
Faint Object Camera And Spectrograph (FOCAS) is completed and now waiting for a commissioning run on the Subaru Telescope atop Mauna Kea. We have developed a software system that includes the control of FOCAS instruments, Multiple Object Slits (MOS) design, and an analyzing package especially for evaluating performances of FOCAS. The control software system consists of several processes: a network interface process, user interface process, a central control engine process, a command dispatcher process, local control units, and a data acquisition system. These processes are mutually controlled by passing messages of commands and their status each other. The control system is also connected to Subaru Observation Software System to achieve high efficiency and reliability of observations. We have two off-line systems: a MOS design program, MDP, and an analyzing package. The MDP is a utility software to select spectroscopy targets in the field of view of FOCAS easily through its GUI and to design MOS plates efficiently. The designed MOS parameters are sent to a laser cutter to make a desirable MOS plate. A special package enables prompt performance check and evaluation of the FOCAS itself during a commissioning period. We describe the overall structure of FOCAS software with some GUI samples.
We show that a crystalline lithium niobate (LiNbO3 : LN) grism and a hybrid grism made of a LN transmission grating and a zinc sulfide (ZnS) prism, in spite of their birefringent properties, can be used as new and powerful dispersing elements with high refractive indices to realize high spectral resolution for optical to near infrared astronomical spectrograph with transmission optics. We also show new fabricating methods for grisms and immersion gratings with high index material and deep grooves.
An observation data set (OD) has an important role in Subaru Observation Software System in order to connect the observation control system with the data analysis system. OD includes abstract commands of getting both a science object data and its calibration data indispensable to calibration. Acquisition conditions of each calibration data are also defined in the OD. The observation schedule may be optimized and re-arranged using the OD during the observation in scheduling mode. In the manual operation mode, indication of the next observation command may be given through the OD. The OD is used for automated data analysis, such as pipeline processing, in the data analysis system in the base facility in Hilo, Hawaii. Feedback of the control parameters and real-time quality assessment of the acquired data to observation scheduling will be achieved using the supercomputer system at Hilo in a few years.
Subaru Observation Control System has selected Ethernet and FiberChannel as their standard interface to instruments. Every instrument should connect themselves with at least one of the LANs. Regarding the data transfer to Hilo base, the first concern is that no data must be lost during transfer process, whatever troubles may happen on hardware or network. In the hardware, we provide RAID, tape library at the summit and another RAID at the base facility. As the other measure in software, we have the data file management by Subaru Observation Software System, which enables users to track the location of the file. The hardware configuration of the summit simulation system, which is for the instrument test and so on, is presented. The telescope at the summit of Mauna Kea has been connected to the super computer at the base facility via OC12. This high-speed network is used not only data transfer and IP communication, but also for multimedia communication such as video or telephone. The multimedia project is introduced.
Subaru telescope observation control system is composed of several systems such as a telescope control system, an observation supervisor system, a data acquisition system, and a data archival system. Each system consists of several processes to carry out observation operation in cooperating with other processes by passing control messages and by exchanging their status data. All acquired data is registered in database together with related data such as status and log data of the telescope and instruments. Observers and their observation proposals are registered in the control system as a NIS+ user and NIS+ group. User access to the control. system is managed according to the registered operation level. User interface of the control system is described with some samples of screen displays.
Subaru telescope of National Astronomical Observatory of Japan is now under the commissioning phase, and there will be installed seven powerful instruments to produce several tens megabytes of data in each second of observations. The total amount of the storage necessary to keep those data becomes about 20TB per year.Here we introduce a concept of the hierarchical data storage system on the super computer system of Hilo Base Facility of Subaru Telescope. Detailed description of the computer system and performance feature is also presented. The computer system is useful for operation support based on advanced information management database, called Subaru Data Base.
KEYWORDS: Telescopes, Mirrors, Digital signal processing, Digital filtering, Control systems, Electroluminescence, Signal processing, Servomechanisms, Control systems design, Filtering (signal processing)
On-shop test erection has been carried out at the Hitachi Zosen factory in Osaka since 1996. The purpose of this on- shop erection is to check and adjust the sizes of parts, to minimize the assembling errors, to test the telescope drive and active support system of the primary mirror, and to review the processes of final assembling. The alt-azimuth Subaru telescope structure weighting 500 ton is supported by six hydrostatic oil-film pads and is driven successfully by direct drive. The additional test for the instrument rotator drives, cable wrappers, and other were also carried out. We report the preliminary results of the control efficiency.
We adopt the hierarchy structure for the telescope control system of the Subaru Telescope. The system is made up of a TSC, three TWSs, three DCMOMs, three MLPs, and many LCUs. All devices are connected through local network each other.
An observation with Subaru Telescope is designed to be executed by the central scheduler process. Control commands are abstracted common to all observation instruments so that the observers are free from the consciousness of the difference between many instruments as much as possible. An abstraction command which is described in an observation procedure is expanded to a device dependent command script, and the script is dispatched to the telescope and instruments by referring to the instrument table. Device dependent commands are processed synchronously or asynchronously by checking the status against interlocks. The structure of the scheduler and the instrument table, the flow of commands such as an abstraction command, a device dependent command script, and a device dependent command, their examples and syntax are described.
Subaru observation software system (SOSS) provides observers with so called high-level user interface, scheduler and data archival system. This paper presents both software and hardware environment for test, debug and development of instrument controller (OBCP) and SOSS. The environment is composed of instrumentation software toolkit, instrumentation software simulator, telescope simulator and summit simulation computer system.
Control software of FOCAS (faint object camera and spectrograph) is being developed as a prototype of control software for SUBARU observing instruments. The software system consists of several processes; a network interface process, a user interface process, a central control engine process, a command dispatcher process, local control units, and a data acquisition system. Each process is communicated to other processes and controlled by passing messages of commands and its status. A control flow and generalized command messages are defined following the software guideline for the SUBARU instruments. Functionality of each process is presented. Related off-line software for making multi-slit plates and for data analysis is briefly described.
The overall updated plan for constructing 7 scientific instruments and 3 baseline programs for the 8 m Subaru telescope is shown. Somewhat detailed descriptions are given further for projects to develop large format CCDs, faint object camera and spectrograph (FOCAS), high dispersion spectrograph (HDS), Subaru prime focus camera (Suprime-Cam), and Cassegrain adaptive optics system (AO).
The control system for the Subaru telescope is designed to consist of distributed workstations, local processors, and data acquisition computers, which are interconnected by control LANs and data LANs. The control software achieves its functionality with message-based communication. Two key processes, a scheduler and a status logger cooperating with any other processes, are designed to perform efficiency and security in observation. Control flow of observation scheduling and functionality of sub-processes which constitutes the scheduler and the status logger are described. For data acquisition from instruments, Subaru control system provides a variety of data highway which enable instruments to transfer data by up to 20 Mbytes/second. Functionality and characteristics of other subsystems which compose the Subaru control system are described.
The concept design of the faint object camera and spectrograph (FOCAS) for the 8.2 m SUBARU telescope (JNLT) is presented. The FOCAS is designed for enabling observations of extremely faint galaxies distributed over a 6 arcmin FOV with spectral resolution of R equals 1000. Fully transmitting optics will produce high quality images better than about 20 micrometers rms diameter over the entire FOV in white light of a wavelength range of 0.365 - 0.9 micrometers . A pair of abuttable CCDs with 4000 x 2000 pixels of 15 micrometers square pixel size are considered to be used. Several observing modes are available with the automated multislit assembly and changable optical elements. Control software coupled with telescope control software enables an automatic observation of several tens of galaxies simultaneously.