CASDA Virtual Observatory CSIRO ASTRONOMY AND SPACE SCIENCE Arkadi Kosmynin 11 March 2014

Presentation outline Virtual observatory Targeted VO protocols Table Access Protocol Simple Spectral Access Protocol Simple Image Access Protocol Cone Search Protocol Minimal set of supported features Likely and/or desirable extensions Used components Architecture CASDA Virtual Observatory | Arkadi Kosmynin 2 |

Virtual Observatory Wikipedia: Virtual observatory (VO) is a collection of interoperating data archives and software tools which utilize the internet to form a scientific research environment in which astronomical research programs can be conducted. CASDA Virtual Observatory | Arkadi Kosmynin 3 | Web sites Data centers Web directory HTTP Topcat Aladin VOP RAP VO registry Easy to explain using the Web analogy WebVO

Table Access Protocol The table access protocol (TAP) defines a service protocol for accessing general table data, including astronomical catalogs as well as general database tables VO protocols. The hardest VO protocol to implement: requires translation from ADQL (Astronomical Data Query Language) and processing requests in synchronous and asynchronous modes. We support: ADQL 2.0 Observation Data Model Core Components (ObsCore) More tables, such as source catalogs, exposed Serving required metadata Possible extensions: R/O access to PostgreSQL level Detailed metadata CASDA Virtual Observatory | Arkadi Kosmynin 4 |

Simple Spectral Access Protocol The Simple Spectral Access (SSA) Protocol (SSAP) defines a uniform interface to remotely discover and access one dimensional spectra. We support: Querying on position, frequency, time, and polarization Serving data Serving required metadata Possible extensions: Remote operations on data cubes (filtering, transformations) Detailed metadata More search parameters CASDA Virtual Observatory | Arkadi Kosmynin 5 |

Simple Image Access Protocol The Simple Image Access (SIA) protocol provides capabilities for the discovery, description, access, and retrieval of multi-dimensional image datasets, including 2-D images as well as data cubes of three or more dimensions. We support: Querying on position, time and frequency (band) Serving data Serving required metadata Possible extensions: Remote operations on data cubes (filtering, transformations) Detailed metadata More search parameters CASDA Virtual Observatory | Arkadi Kosmynin 6 |

Cone Search Protocol The VO Cone Search protocol is a simple query protocol for retrieving records from a catalog of astronomical sources. The query describes sky position and an angular distance, defining a cone on the sky. We support: Search on position with a given radius Serving records matching the search Serving related data Serving required metadata Possible extensions: Detailed metadata CASDA Virtual Observatory | Arkadi Kosmynin 7 |

Used Components Selection criteria: Support the Cone Search, Simple Image Access, Simple Spectral Access and Table Access VO protocols Be actively supported either by community or authors Be in active use in at least a few organisations Be written in Java or have a Java interface/client Be designed to be used by third parties Not to be locked to a particular database structure Be efficient: capable of handling 20,000-30,000 records per query in a reasonable time Considered: SAADA, DALServer, VO-Dance, GAVO DaCHS, OpenCADC, DALToolkit, DSA, STIL, STILTS, CDS Libraries Selected: CDS Libraries (SAVOT, UWS, ADQL) CASDA Virtual Observatory | Arkadi Kosmynin 8 |

Architecture CASDA Virtual Observatory | Arkadi Kosmynin 9 |

Where are we now? Have a working prototype: Extendable architecture Implemented TAP Implemented SSAP Cone Search works on top of TAP About 4-5 days away from finishing SIAP Works with Topcat All jobs can run in asynchronous as well as synchronous mode Keeping in touch with AUSVO group CASDA Virtual Observatory | Arkadi Kosmynin 10 |

Thank you CASDA Virtual Observatory | Arkadi Kosmynin 11 |