普适图像传输系统(Flexible Image Transport System,FITS)是天文学领域应用最广泛的数据格式。自从20世纪80年代FITS格式被国际天文联合会(IAU)正式公布为国际标准以来,大部分的天文数据都是以FITS文件的形式在世界各地的数据中心和天文学家手中保存和交换。采用文件系统方式保存管理的FITS数据文件,很难适应程序化的检索和定位需求。随着FITS文件数量的不断增加以及虚拟天文台技术的发展,为这些以文件形式保存的天文数据提供检索功能的需求越来越迫切。FITS头以关键词值对的形式确切定义了所属FITS文件的结构,还提供了数据本身诸多特性的重要信息。FITS头中保存的这些信息可以满足大部分FITS数据文件查询检索的需求。将FITS头中的信息利用数据库来保存和管理,可以极大的方便对FITS文件的检索和定位。FITS头归档入库系统(FitHAS)是中国虚拟天文台项目开发的一个简单实用的FITS头信息归档入库工具,能够方便的将单个或者多个FITS文件的主FITS头信息导入到数据库中,为FITS数据文件的查询检索奠定基础,进而为虚拟天文台等更高层次的数据访问服务部署创造条件。本文介绍FITS数据格式,FITS头的基本结构;探讨虚拟天文台环境下FITS数据文件检索定位的实现方式;阐述FitHAS的功能特点、设计开发和使用方法。
Flexible Image Transport System (FITS) is the widest adopted data format in astronomy. Since FITS was endorsed by the International Astronomical Union (IAU) for the interchange of astronomical data in 1980s, most of astronomical data are stored by and exchanged among astronomers and world - wide data centers. FITS files, stored and managed by Operation System (OS) file systems, can hardly be searchable and locatable. With the rapid increase of the number of FITS files, and development and popularization of Virtual Observatory ( VO), it is more and more urgent to provide on - line search and access functions for FITS files stored in file systems. The keyword records in FITS header provide exact description of the structure of the corresponding FITS file, but also give much important information of the data stored in the file. Most of search requirements on FITS files can be satisfied by information taken from primary header keyword records. Storing and managing keyword records using DataBase Management System (DBMS) will make FITS file searching easily and flexible. FITS Header Archiving System (FitHAS) is a simple but useful application developed by Chinese Virtual Observatory (China- VO ) project. With FitHAS, the keyword record information for one or more FITS files under a given directory can be imported into a database easily. Basing on the keyword database, FITS files can be searched and located. A little further, advanced data access systems including VO can be deployed. In the paper, basic knowledge of FITS and FITS header are introduced, searching and accessing of FITS files in VO environments are discussed, and functions, characters, design and development of FitHAS are described.