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Google Sky

Google Sky. Worldwide R&D of Virtual Observatory. Chenzhou CUI Chinese Virtual Observatory Project National Astronomical Observatory of China. Content. VO Introduction IVOA status, specifications and highlights R&D activities from China-VO. VO concept.

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Google Sky

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  1. Google Sky

  2. Worldwide R&D of Virtual Observatory Chenzhou CUI Chinese Virtual Observatory Project National Astronomical Observatory of China

  3. Content • VO Introduction • IVOA status, specifications and highlights • R&D activities from China-VO CANS 2007, Aug. 25-26, 2007, Xi'an

  4. VO concept • Virtual Observatory (VO) is a data-intensively online astronomical research and education environment, taking advantages of advanced information technologies to achieve seamless, global access to astronomical information. • The power of the World Wide Web is its transparency. It is as if all the documents in the world are inside your PC. The idea of the Virtual Observatory is to achieve the same transparency for astronomical data and other related information (Quinn et al. 2004). CANS 2007, Aug. 25-26, 2007, Xi'an

  5. IVOA in Growth • International Virtual Observatory Alliance (IVOA) • formed in June 2002 • with a mission to facilitate the international coordination and collaboration necessary for the development and deployment of the tools, systems and organizational structures necessary to enable the international utilization of astronomical archives as an integrated and interoperating virtual observatory. CANS 2007, Aug. 25-26, 2007, Xi'an

  6. Science driven, technic enabled VO drivers : science • multi-archive research • Precision Cosmology • The Time Domain • A Panchromatic approach to the Universe… CANS 2007, Aug. 25-26, 2007, Xi'an

  7. Science driven, technic enabled VO drivers : technology • hardware trends • ops, storage, bw : all 1000x/decade • data i/o bw 10x/decade • data avalanche • CCD array • digital sky survey • numerical simulation CANS 2007, Aug. 25-26, 2007, Xi'an

  8. VO framework • agreed standards • inter-operable data collections • inter-operable software modules • no central VO-command - its not a thing - its a way of life CANS 2007, Aug. 25-26, 2007, Xi'an

  9. What the Virtual Observatory is… • A suite of international standards for the discovery, exchange, intercomparison, and analysis of network-accessible astronomical data • A data access and analysis environment that exploits the emerging computation/software/data Grid • A framework for data processing that enables and encourages the re-use of algorithms • A tool for science planning: Identify gaps in coverage of parameter space. Which new missions, instruments, experiments will have largest impact? • A catalyst for world-wide access to astronomical archives • A routinely used tool of the research astronomer • A vehicle for education and public outreach It is not a thing VO is a way of life CANS 2007, Aug. 25-26, 2007, Xi'an

  10. what is needed ? • global standards • well funded data centres • working data services • infrastructure software • VO aware client tools • VO aware data mining services CANS 2007, Aug. 25-26, 2007, Xi'an

  11. IVOA Protocols key for interoperability

  12. Protocol List • VOTable • FITS • Cone Search Protocol • Simple Image Access (SIA) Protocol • Simple Spectral Access (SSA) Protocol • SkyNode • Astronomical Data Query Language (ADQL) • Uniform Column Descriptors (UCDs) • Space-Time Coordinates (STC) • IVOA Identifiers • VO Registry • Resource Metadata • Registry Access Protocols • OAI • VOEvent • NESSSI • VOSpace • PLASTIC • Common Execution Architecture • Request-Object Management Environment (ROME) CANS 2007, Aug. 25-26, 2007, Xi'an

  13. Formats • VOTable • XML format for tabular information • Catalog query results • List of images or spectra • Lists of resources • Includes UCDs for columns • FITS • Standard astronomical binary data format • Images, spectra, … CANS 2007, Aug. 25-26, 2007, Xi'an

  14. Data Access Protocols • Cone search • Simple query around a given region • Returns VOTables • Simple image access • What images overlap a given region? • Create me an image of this region. • First step produces VOTables with links to image • User downloads images as FITS in second stage • Simple spectral access • What spectra are available within this region • More sophisticated than SIA (includes support for Data Models) but uses comparable framework • SkyNode • SOAP Web-Service based • Sophisticated access to tables • Supports distributed queries • Uses ADQL • Should eventually subsume Cone-search CANS 2007, Aug. 25-26, 2007, Xi'an

  15. Query languages • Astonomical Data Query Language (ADQL) • Enhanced version of SQL to support astronomical queries • Positional cross-correlations (XMATCH) • Complex regions on the sky (REGION) • Both SQL-like and XML representations CANS 2007, Aug. 25-26, 2007, Xi'an

  16. Semantic content • IVOA identifiers • Scheme for providing unique identifiers for any thing that needs to be distinguished. Services, requests, … • ivo://authority/authority_controlled_string#sub-resource • Used in registries and other protocols • Resource metadata • Standardized format for the description of a service, data collection, facility. • XML format based on the Dublin-core metadata descriptions for published resources. • Used inside registries. • Uniform Column/Content Descriptors (UCDs) • Standardized names for table columns with relatively high degree of specificity. • pos.eq.ra or phot.flux;em.ir • Used in VOTables and by Cone search and SIA • Space/Time Coordinates • Way of specifying points or regions of space-time. • Can be simple or very complex • Used in ADQL and VOEvent CANS 2007, Aug. 25-26, 2007, Xi'an

  17. Discovering Resources • Registry • Collection of resources that users can find included Cone Search, SIA, SSA and SkyNodes. • User access via registry access protocol • Registry-registry communication via OAI • Some publishing registries are meant to be seen only by other registries • Registry access • How users query the registry • In standards process • Open Archive Interface (OAI) • Library community standard • Registry-registry communication to ensure that all registries are up to date. • VOEvent • VO protocol for publishing and receiving notice of transient/urgent events • Describes events using STC CANS 2007, Aug. 25-26, 2007, Xi'an

  18. Accessing and Controlling Computer Resources • NESSI • NVO Extensible, Scalable, Secure Service Infrastructure • Provide access to protected resources, especially Grid computational resources. • Make it easy to do simple things. • First implementations just coming on-line • VOSpace • Access to storage resources in a standardized way. • PLASTIC • Platform for Astronomical Task InterCommunication • Applications publish and receive notifications of events from other applications (e.g., selection of a given object) to enable coordinated actions. • TOPCAT – Aladin • Deployed but still experimental. • Common Execution Environment (CEA) • Script/pipeline environment with security and such incorporated (Astrogrid) • ROME • Handle and schedule tasks that involve remote resources. CANS 2007, Aug. 25-26, 2007, Xi'an

  19. Highlights from VO • VO Infrastructures • VO-oriented application • Miscellaneous tools CANS 2007, Aug. 25-26, 2007, Xi'an

  20. CANS 2007, Aug. 25-26, 2007, Xi'an

  21. Astrogrid Components • Registry • Community • FileManager/Filestore • Workflow& Job Execution Service (JES) • Common Execution Architecture (CEA) • DataSet Access (DSA) • Workbench CANS 2007, Aug. 25-26, 2007, Xi'an

  22. Aladin V4 – CDS (Euro-VO) • Aladin v4 • an interactive software sky atlas developed by CDS • MultiView, multiProjection • Resampling • Blinking: builds on the fly image sequences (slow movies) • GIF, JPEG and PNG support • Cut graph: along any segment • Cross match algorithm: for better object catalog analysis • Multi-language CANS 2007, Aug. 25-26, 2007, Xi'an

  23. NVO Core Services • NVO Registry Portal: Find source catalogs, observation logs, image archives, and other astronomical resources registered with the NVO • DataScope:Discover and Explore Data in the Virtual Observatory • Open SkyQuery: Cross match yoru data with numerous catalogs • NVO Spectrum Services: Search, plot, and retrieve SDSS, 2dF, and other spectra • Web Source Extractor Upload images to SExtractor and cross-correlate the objects found with selected survey catalogs. CANS 2007, Aug. 25-26, 2007, Xi'an

  24. CANS 2007, Aug. 25-26, 2007, Xi'an

  25. VOPlot Tools from VO-India A VO-I + CDS collaboration VOPLot VOPLot3DVOMegaPLot CANS 2007, Aug. 25-26, 2007, Xi'an

  26. China-VO History and current status

  27. R&D Focuses • China-VO Platform • 中国虚拟天文台系统平台的开发 • Unified Access to On-line Astronomical Resources and Services • 国内外天文研究资源的统一访问 • VO-ready Projects and Facilities • 支持VO的项目与观测设施 • VO-based Astronomical Research Activities • 基于VO的天文研究示范 • VO-based Public Education • 基于VO的天文科普教育 CANS 2007, Aug. 25-26, 2007, Xi'an

  28. Two XSLT transforms • VOFilter • an XML filter for OpenOffice.org Calc to open VOTable files • http://services.china-vo.org/vofilter/ • VOTable2XHTML • a stylesheet to transform VOTable data into HTML/XHTML format • http://services.china-vo.org/votable2xhtml/ CANS 2007, Aug. 25-26, 2007, Xi'an

  29. VO Data Access Service (VO-DAS) • An OGSA-DAI based service system to provide unified access to astronomy data, including catalogs, images and spectra. • Goals of VO-DAS • Supporting high volume data query • Interlinking distributed and heterogeneous archives • catalogs, images, spectrums • Providing a software that works for astronomers • OGSA-DAI Supported Asynchronous Data Access Service • OGSA-DAI is a middleware product which supports the exposure of data resources, such as relational or XML databases, on to grids. • Work with Globus Toolkit 4 • WSRF interface • Good wrapper for variant databases • Asynchronous query supported • Available for large dataset CANS 2007, Aug. 25-26, 2007, Xi'an

  30. Status • An Alpha version of VO-DAS was ready • Query Workflow • Synchronous Query • Asynchronous Query • Asynchronous Query on multiple DataNodes CANS 2007, Aug. 25-26, 2007, Xi'an

  31. SkyMouse: Touch the sky with your mouse • Not like some VO efforts on unified access systems, for example, NVO DataScope, SkyMouse tries to show a comprehensive overview for a specific object, but not to snatch as much data as possible. CANS 2007, Aug. 25-26, 2007, Xi'an

  32. VO Trends • VO is inevitable, a new way of doing science • Present on every physical scale today, not just astronomy (NEON, Neptune, CERN, MS) • Driven by advances in technology, and economics, mapped onto society CANS 2007, Aug. 25-26, 2007, Xi'an

  33. Q & A ? www. .org CANS 2007, Aug. 25-26, 2007, Xi'an

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