Development of an Astronomical Data Archive System

We have developed a data archive system for the optical telescopes of Okayama Astrophysical Observatory and Kiso Observatory. The system, called MOKA (MitaKa　Okayama Kiso Archive system), is not only the first network-accessible astronomical archive system in Japan but also the prototype of the data archive system of Subaru Telescope. Archival data contain much information besides that the observer intends to extract. It is often that an important object is found into the image, or an　unimaginable phenomenon is caught in the image by chance. It is certain that　comparing data obtained in various wavelength regions presents new prospects of　the object. Archival data of Subaru Telescope, which mounts the wide-field imaging　camera and other characteristic instruments, are expected to bring many fruitful　results for us. The archives for space mission data exist since 1970's, but it is in recent　years that the construction of archives for ground-based telescopes has begun. The　most crucial reason is the difficulty in reuse of the data, which is caused by　the non-uniformity of the data quality. The observing procedure of ground-based　observations is not definite but is freely determined by each observer, and the　configuration of observational instruments is often changed. Moreover, atmospheric environment, such as weather condition, seeing, etc., also influences the quality of ground-based observational data very much. Hence, in order to retrieve valuable data quickly and to analyze them with high precision, it is essential to evaluate the data quality and to examine the environment of the observation. There exist several archive systems which provide the shrunk preview images　of the CCD frames and the atmospheric parameters at the observation, but the　functions are insufficient for evaluating the data quality or for examining the　observational environment. In order to inspect an imaging frame in detail, it is　desired to show the image with various tonal ranges. Also, for the examination of　a spectroscopic frame, the function of extracting the spectrum from the frame is　essential. For the environmental information, an archival user needs the time　variation of meteorological parameters rather than the parameters at a point in　time. The above functions are indispensable for ground-based data archives to make　its scientific productivity maximum. That is why we have developed a new data archive　system. The functions of MOKA are provided by the user interface, which allows users　to have access to MOKA from various computer platforms through the WWW (World Wide　Web). Using the user interface with a WWW browser, archival users can access data　objects of MOKA, which are a header information database, header information (HDI)　files, quick-look image (QLI) files, and weather/sky-monitor databases, etc. The most characteristic feature of MOKA is the highly functional user interface for evaluating the data quality and examining the observational environment. The QLI viewer shows the quick-look image of a CCD frame with the user-adjustable tonal range and with the profile along an arbitrary row or column. Those functions are helpful for inspecting details of the images and the spectra, and indispensable for evaluating the data quality and for picking up data for request. The QLI viewer is a Java applet, so that it needs no installation onto any client computers and runs on most of WWW browsers that support Java. The QLI viewer is the only previewer of the archive systems in the world which realizes the above-mentioned functions on any computer platforms. The meteorological data viewer and the night-sky image viewer are invoked from each CCD frame in the result list of the search and are used to examine the observational environment. The meteorological data viewer displays the data of six hours around the observation time of the frame, and the night-sky image viewer shows the image at the closest time of the observation. Since the atmospheric conditions affects observational data very much, the examination of the atmospheric variation around the time of the observation is essential to evaluating the data quality. MOKA is the only data archive system in the world which integrates the environmental data with the observational data. The Java technology is adopted not only for the above three viewers but also for the most part of the user interface of MOKA. Java realizes interoperability beyond the difference of computer platforms, and reduces redundant network traffic. There are several multi-mode, multi-spectral instruments planned for Subaru Telescope. Though the identification and the retrieval of calibration frames are the very essential procedure for an archival user, the relation of the calibration frames with the object frames between the observational modes is very complex for multi-mode instruments, since the calibration frames are often used in common beyond the observational mode ...

application/pdf

総研大乙第76号

博士論文

資料形態 : テキストデータ プレーンテキスト
コレクション : 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文
博士論文