Hello!. Virtual Observatories. Ajit Kembhavi IUCAA Pune, India. Data Storage and Retrieval. The Astronomer Vermeer 1632-1675. The Library of Alexandria 3 rd Century BC. The Data Avalanche. Immense amounts of data are being produced by large telescopes using large area detectors.
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Data Storage and Retrieval
The Library of Alexandria
3rd Century BC
Immense amounts of data are being produced by large telescopes using large area detectors.
Terabytesof data are now available, andPetabyteswill soon be available from frequent all sky imaging.
Vast databases are also being produced throughsimulations.
~ 100 Gb/night
The data spans the electromagnetic spectrum from the radio to the gamma-ray region.
Obtaining, analysing and interpreting the data in different wavebands involves highly specialised instruments and techniques.
The astronomer needs new tools for using this wealth of data in multiwavelength studies.
Members of the IVOA
Empower astronomers by providing sophisticated query and computational tools, and computing grids for producing new science.
The IVOA has identified six major technical initiatives to fulfill the scientific goal of the VO concept.
REGISTRIES: These collect metadata about data resources and information services into a queryable database. The registry is distributed. A variety of industry standards are being investigated.
DATA MODELS: This initiative aims to define the common elements of astronomical data structures and to provide a framework to describe their relationships.
UNIFORM CONTENT DESCRIPTORS: These will provide the common language for for metadata definitions for the VO.
DATA ACCESS LAYER:This provides a standardized access mechanisms to distributed data objects. Initial prototypes are a Cone Search Protocol and a simple Image Access Protocol.
VO QUERY LANGUAGE:This will provide a standard query language which will go beyond the limitations of SQL.
VOTable: This is an XML mark-up standard for astronomical tables.
Virtual Observatory -India
A collaboration between IUCAA and PSPL,
with a grant from the Ministry of Communications and Information Technology
Persistent Systems Pvt. Ltd., Pune
Vizier, Aladin, ADS
VOPlot Visualizer for catalogue data
VOTable C++ Parser
VOTable Streaming writer
User interfaces and query tools
Applications beyond astronomy
All tools have web-based and stand alone versions
Visualization and simple statistics of catalogue data. Integration with sky atlases.
A VO-I + CDS collaboration
First conceived as a web-based tool for Vizier
Then integrated with Aladin
VOPlot is now also a stand alone system
It has been integrated with many data bases
Sonali Kale, K.D. Balaji et. Al.
Catalog Data Interface Tool
A tool to query catalog data.
Simple, customizable, graphic interface.
Not specific to type of data or catalogue.
SQL queries for expert users.
VO tools available for analysis:
VOPlot, Aladin,VOStat, SIMBAD, NED...
Data Organization and Architecture
Browse Server Database
Query using a Form
Query using SQL Directly
Results in VOPlot
Results in Aladin
High proper motion L-subdwarf
Optical spectra of mixed late M and mid L type
Only the third L subdwarf known
0.617 arcsec / yr
AVO Prototype Demo
Astronomy Catalogue Extractor
View, create and add to FITS files
Convert to other formats
Acts on a data array in memory
to convert it to the VOTable form,
which is streamed row by row
to an output file. Very large
VOTables can be written without
The data part in a VOTable may be represented using one of three different formats:
Sonali Kale, Sudip Khanna
XSL Transformations (XSLT) and the
XML Path language (XPath).
IUCAA HPC Facility Hercules
HPC Team :
Co-proposed by :
> 30 G flops
Preliminary HPL benchmark
Linpack 1000x1000: 6847
Caltech, Fermilab, JHU, NASA/HEARC, Microsoft, NCSA/UIUC, NOAO, NRAO, Raytheon ITS, SDSC/UCSD, SAO/CXC, STScI, UPenn, UPitts/CMU, UWis, USC, USNO, USRA, CVO
Inter-University Centre for Astronomy and Astrophysics
Registry and DIS
Raid 5, 4 Terabyte
- Released on May 31st , 2002.
- Support only for reading of tables.
- Support only for pure-XML TABLEDATA and not for BINARY or FITS data streams.
- Runs on Windows NT 4.0, Windows 2000 and
RedHat Linux 7.1.
- Can be incorporated quickly and efficiently.
from the <RESOURCE> element in VOTable
API – Typical Operations
What is in Release V1.1
VOTable Parser Demo