Viewing and Features

1
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.
Guide Star Catalog-II Jini Enabled Interface
G. Greene1, W. OMullane2, B. McLean1 1Space
Telescope Science Institute, 2ESA/ESTEC
ShowSky - a Jini aware Applet/API astronomical
archive discovery tool
Why Jini?
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.
Object-Oriented Configuration
Rational Rose 2000 - component and logical
model JAVA code generation Software
Infrastructure - JAVA 1.2.2 (1.3 ok), Jini
1_1, JAI 1_0_2, nomfits Open Source Software
Object Design and Implementation

Jini Servers

• Servers
• Many 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).

• Broadcast
• JINI 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.

• Activatable Jini Services
• The 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.

Viewing and Features

• Multiple 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

• Special 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

• Filtering
• 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.

Acknowledgements The 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.