天文观测数据资源具有时间跨度大,数据量大,存储、管理分散,管理工具驳杂等特点。如何提供给天文学家一个统一访问这些异地存放的异构数据资源的方案,是虚拟天文台的一个重要研究课题。本文提出了一种基于网格的解决方案。我们基于OGSA—DAI技术实现了对天文星表数据,图像数据和光谱数据的封装(DataNode)。我们设计的虚拟天文台数据访问服务(VO—DAS)实现了对DataNode的自动资源发现以及异地异构数据库的联合访问。这将使天体的多波段交叉证认成为可能。VO—DAS支持国际虚拟天文台联盟(IVOA)的各项相关标准,使得它具有良好的互操作性。它的对外接口简单实用,可以针对不同需求的天文数据用户发展出多种网格应用产品。通过在两个科学范例中应用VO—DAS服务,证明了它的可行性。
Astronomical data resources have features of the long - term accumulation, high volume, distributed storage, and managed by the diverse database software. One of the important goals in Virtual Observatory (VO) is to provide an uniformed way to access these distributed and heterogeneous data resources for astronomers. A grid solution (Virtual Observatory Data Access Service, VO - DAS) is designed in this paper. Astronomical catalogue data, image data and spectroscopy data, which have different metadata, are wrapped by OGSA- DAI (DataNode). VO -DAS implements automatic discovery of DataNodes and supports federation data access upon them. This makes it possible for multi - band cross matching of astronomical objects. VO -DAS supports related specifications published by International Virtual Observatory Alliance (IVOA) so that interoperability is achieved. A series of simple and efficient application interface are designed for developing versatile high - level applications based on VO - DAS. Two science cases based on VO - DAS confirm its feasibility.