Viewing and FeaturesViewing and Features

ShowSky - a Jini aware Applet/API astronomical archive discovery tool

Object Design and ImplementationObject Design and Implementation

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A Demonstration of Jini Technology applied to Astronomical Archives

A visualization tool has been developed for accessing both astronomical image and catalog archives using Jini. This technology provides many inherent features which are beneficial in managing a distributed community of archive services. Using the GSC-2 export catalog, the COMPASS database, and the DSS image archive at STScI, an extensible object-model was designed to include cross access to these internal datasets as well as external archives such as Hipparcos, Tycho, and the SDSS Science Archive. What is presented here are the

JAVA components and the Jini architecture as applied to a query for small field acquisition, viewing, and analysis that is conducive to multi-archive interoperation.

Multiple Catalog ViewingMultiple Catalog Viewing• Users may select several source or image catalogues to overlay. We have found this to be essential for quality control in the GSC-II project.

• Publicly available archives• Listing the sources in a Table - “Star, Galaxy, etc. List”

• grouped by catalog • sources from each selected catalogue which are in the current field of view• matches selected filter options

ShowSky Catalog and Image Community A simplified view Service-based architectures are one of the simplest

systems to design, maintain, and enhance. They support network growth as both the internal complexity of a network evolves as well as expansion to external network connectivity. There is a shift from a brittle wire-based network to a distributed set of services with failover protection insured by strategic placement of services. As the network contencts change, a Jini community can adapt to what is present.

FilteringFiltering• Allows filtering of the displayed sources• Selections for

• Magnitude Range• Source Classification• Band Code• Propermotion

• The COMPASS filter applies only to catalog sources coming from the COMPASS database. More field will be added to this in due course.

Special FeaturesSpecial Features

Multiple Catalog Viewing• It is possible to select several source or image catalogues to overlay both for quality control inspection

Animation• Proper motions are available for some GSCII stars and all ESA'S Hipparcos and Tycho Catalogue entries. This tool uses the proper motion information to plot star motions into the future. The motion Panel on the right of the tool allows the user to select a step (how fast the animation goes) in years and checkbox for tails. When "tails" are selected the old star is not un-plotted so a tail effect is seen showing the path of motion.

Hierarchical Triangulated Mesh

• Object naming scheme common to multiple archives based on Spatial subdivision of celestial sphere using quad-tree algorithm

• 4 spherical triangles at each level

AcknowledgementsAcknowledgementsThe Digitized Sky Surveys and Guide Star Catalogs are produced by the Catalogs and Surveys Branch of the Space Telescope Science Institute with the support and assistance of the following institutions. The Association of Universities for

Research in Astronomy, National Aeronautics and Space Administration, Osservatorio Astronomico di Torino, European Southern Observatory, Space Telescope European Coordinating Facility, International GEMINI Telescope, European Space Agency Astrophysics Division, Canadian Astronomical Data Center, Centre de Données astronomiques de Strasbourg, Anglo Australian Observatory, Royal Observatory Edinburgh, Palomar Observatory, National Astronomical

Observatory of Japan, Beijing Astronomical Observatory, Astronomical Society of the Pacific.

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Why Jini?Why Jini?

JINI service

Http

RMI transportCOMPASSooDB

GSC-2

GSC-I

Tycho

Hipparcos

DSS

ShowSky

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ArchiveServer

SDSS

JINI registered ArchiveServer allows WWW served archives to joincommunity. RMI archives registered as separate JINI services.

Jini ServersJini Servers Archive Server

ServersServersMany servers and services may be made available via JINI. Any machine may be used to host the JINI services. The main service required here is the lookup service called reggie. Reggie requires rmid (The RMI activation daemon).

ShowSky PackageShowSky Package

Object-Oriented ConfigurationObject-Oriented Configuration

ClientClient

BroadcastBroadcastJINI discovery works on broadcasts and as such will not work over WAN. There is however also the possibility to provide one or more hostnames which should be checked as well as doing a broadcast. This provides the best of both worlds. The JINI servers and the JINI client have been written to take advantage of this. A host name may be specified in the property LOOKUPURL in a propertyfile. Then this host will be searched/used for registration. Should this host not be running reggie the broadcast will still find another host on the network running reggie if possible.

Rational Rose 2000 - component and logical model

JAVA code generationSoftware Infrastructure - JAVA 1.2.2 (1.3 ok),

Jini 1_1, JAI 1_0_2, nomfitsOpen Source Software

Activatable Jini ServicesActivatable Jini ServicesThe class.stsci.server.LaunchService is provided to launch Activatable servers and register them with the rmi activation registry. For this to work rmid must be running on the machine. RMID keeps a log of activated services and restarts them each time rmid restarts.