PH512
Lecture 2: Grids Professor Michael Smith
MULTIMEDIA ASTRONOMY
School of Physical Sciences
Convenor Prof. Michael Smith
Taught in Spring Term Kent Credits 15 at Level H
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PH512
ECTS Credits 7.5
Grids & Virtual Observatories (VOs):
Terabytes. Astronomy faces a data avalanche.
Breakthroughs in telescope, detector, and computer
technology allow astronomical surveys to produce
terabytes of images and catalogs.
(one terabyte comprises 1000 gigabytes)
These datasets will cover the sky in different
wavebands, from gamma- and X-rays, optical,
infrared, through to radio. In a few years it will be
easier to "dial-up" a part of the sky than wait
many months to access a telescope.
Astrogrid
http://www2.astrogrid.org/
Allows remote processing within the VO infrastructure, which
facilitates data access across archives and integrate a large
number of analysis tools
AstroGrid: UK government funded, open source project
designed to create a working Virtual Observatory for UK
and International astronomers.
Working closely with other VO projects worldwide
through the International Virtual Observatory Alliance
(IVOA), internationally recognised interface standards
are emerging which promote true scientific
interoperability of astronomical data and processing
resources worldwide.
The US National Virtual Observatory
PH512
Lecture 2: Grids Professor Michael Smith
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http://www.us-vo.org/
The European Virtual Observatory EURO-VO
http://www.euro-vo.org/pub/fc/software.html
Pipelines & Reduction Packages:
Astro Data Analysis Systems are:
IRAF, MIDAS, Starlink, AIPS,
Image Analysis tools include:
IDL, gimp, PhotoShop, MATLAB, …….
When the first major data analysis systems for optical
astronomy were developed in the 1980s they were a huge
success. For the first time a large body of applications were
available which worked together.
The environment imposed a standard data format (MIDAS
BDFs etc), a useful scripting language (the IRAF CL
perhaps), lots of useful graphics and a standardised
application interface. Many people adopted one and worked
"within" it for much of their processing. The overall effect on
data handling efficiency was strongly positive.
Although much reduction and analysis is still done this way
the situation has evolved dramatically. The standardisation
which was once imposed by the environment is now coming
from outside.
FITS files are universal for data on disk.
The Spitzer mission has not adopted a standard
environment. It has a powerful pipeline system and a
small number of specific tools (Mopex for example, a
flexible mosaicing system, and SPICE, a spectral tool
working on pipeline products) for post-pipeline analysis.
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Lecture 2: Grids Professor Michael Smith
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Pipelined Data: Indeed most major new astronomical
facilities now put much more effort into trying to deliver high
quality data products from pipeline processing rather than
into the exploitation or development of software
environments.
ESO successfully went this way, as did Hubble and more
recently Spitzer. Although this approach doesn't normally
improve on "hand-crafted" data products it is catching up for example Hubble will soon offer combined dithered
imaging data as a pipeline product. On-the-fly calibrated
Hubble data is now taken as the best available for many
uses.
Going beyond standard pipeline processing, many valuable
data sets are now processed to create optimised "high-level
data products" which are ready for immediate science.
The development of more and more effective pipelines
means that one application of the original data analysis
environments, data reduction, is now largely redundant.
The pipelines can use whatever software architecture fits
the observatory delivering the products, without affecting
the utility of the (standardised) data subsequently analysed
by external users.
More and more data is taken from an archive in
processed form rather than processed by astronomers
themselves. High level data products - such as the Hubble
Ultra Deep Field images for example - are of a much higher
standard than most astronomers could process for
themselves and are available for dramatically less effort.
The move towards the VO continues the trend and is
generating more universal standards for data exchange
(VOTable) and remote data access (SAIP and the shift in
front end processing from standard analysis systems to
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Lecture 2: Grids Professor Michael Smith
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pipelines and high-level data products is complemented by
a major change at the backend - the inspection,
measurement and analysis of final data products.
In this case the Virtual Observatory initiatives are creating a
small, but rapidly evolving set of powerful tools which allow
scientific analysis either online from remote datasets, or by
running tools on remote servers.
In future such tools, similar to and developed from current
pilot examples such as Aladin and the AVO Prototype, will
gradually take on many of the important analysis tools.
Aladin
Aladin An interactive software sky atlas allowing the user to
visualize digitized images of any part of the sky, to superimpose
entries from astronomical catalogs
http://aladin.u-strasbg.fr/aladin.gml
Skyview
SkyView is a Virtual Observatory on the Net generating images of any part of the
sky at wavelengths in all regimes from Radio to Gamma-Ray.
http://skyview.gsfc.nasa.gov/
Subaru
Subaru Image Processor: Makali`i is the software which can analyze the
FITS image (data) obtained by the research observation including the Subaru
Telescope. If it is non-commercial educational/out-reach/research purpose, anyone
can use Makali`i freely.
http://makalii.mtk.nao.ac.jp/index.html.en
* Environment of operation:
o Windows OS ( Windows 98/2000 /Me/XP )
* The main functions of Makali`i:
o Aperture Photometry (measuring the brightness of stars)
o Astrometry ()
o Graph (makeing a location-count graph)
o Arithmetic Operation on Image(s) (addition, subtruction, multiplication,
division, ...)
o Blink (displaying multiple images alternately)
PH512
Lecture 2: Grids Professor Michael Smith
etc.
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