STAR

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STAR
Building an Observational GRID
Alasdair Allan Tim Naylor University of
Exeter Iain Steele Dave Carter Jason
Etherton Chris Mottram Liverpool John Moores
University Themis Bowcock University of
Liverpool
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Imagine a system which...
Has unified access to archived data
catalogues, and to telescopes, and to
bibliographic data, and has intelligent software
agents to handle the results.
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The eSTAR Project
Funded by the UK's Department of Trade and
Industry as an e-Science Demonstrator
Project Prototype robotic telescope network
developed to test the computing infrastructure
which could be used for larger scale
projects Consists of a network of telescopes
with associated rapid reduction pipelines, and
intelligent agents (IAs) which examine the data
and, if required, request follow-up observations
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Science Drivers
Not just a cool toy... 021103UT Shutter
closes on a wide-angle CCD image
of Centaurus taken with a large camera
lens 021230UT The data have been processed,
and a list of magnitudes and
positions in made available
on the astronomical data grid 021245UT
Astronomer's intelligent agent has compared
the source list with archive data,
finding a bright object
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Science Drivers
021300UT In response to the IA's request for
confirmation a small
telescope slews to acquire another
image. Whilst waiting for this the IA
queries SIMBAD and discovers
there is no known variable at
this position 021506UT The new image confirms
the object, so the IA
requests spectroscopy from the LT. During
this waiting period the IA pulls all
the other available data and
papers
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Science Drivers
022234UT The IA recognises that the spectrum is
odd. There hasn't been a
?-ray burst, but VISTA shows
a very faint red object mentioned in a
paper last year 022250UT Less than
11 minutes after the initial exposure
the IA has exhausted its understanding so
it wakes up an astronomer
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The Observational Grid
Analogous to Computational Grids No overall
supervisor, which gives the system
scalability. IA's submit requests to nodes on the
network, not commands IA's also do datamining
from databases such as SIMBAD and ADS, catalogues
such as the USNO-A2 , and surveys such as the
DSS Databases only a special cases of
telescopes, that can return data instantly, no
other difference
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The Intelligent Agent (IA)
Can view the system as a unified information
grid, within which intelligent agents live IA's
are developed by astronomers to address their
own science drivers, and can request and
interpret data Scalable, multiple agents can
talk to multiple nodes
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IA Architecture
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IA Prototype
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The Discovery Node (DN)
For the eSTAR prototype these are Meade LX200 and
ETX telescopes with SBIG and Apogee CCD
cameras In general any telescope or archive
which delivers astronomical data or other
resources using a uniform interface Again, there
is no difference between a telescope and a
database except the timestamps
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Communications
IA carries out resource discovery, using LDAP to
find nodes that can carry out a particular type
of observation Each node returns a score to the
IA IA selects the best scoring node, and
requests that it carry out the observation Once
the observation is complete the DN make the
raw data, reduced data and a point source
catalogue available to the IA
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Middleware
Uses Globus IO to transport RTML
documents Globus IO provides user and host
authentication SSL encryption provides a secure
data stream New version of RTML (v2.1) developed
for eSTAR which has been rolled back into the
official version
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Overall Architecture
Surveys Catalogues
Telescope Pipeline
Intelligent Agents
The Grid
Bibliographic Database
Object Database
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Where now?
Next generation IA will use SOAP and WDSL Will
make use of Web Services and Computational
Grids We're looking to deploy the system on
research class telescopes such as the Liverpool
Telescope and UKIRT
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Non - astronomical Applications
Time critical threat reaction Security and
Surveillance systems Earth Observation
Scheduling e-Commerce?
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Summary
The idea of requesting observations is
important This allows telescope nodes to reject
request from an IA if, for example, the
astronomer has no allocated time on the
telescope Important that federated databases and
telescopes share a common interface, there is no
fundamental difference between them other than
the time it takes to return the data and the date
stamp See our website www.estar.org.uk
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