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Hello!. Virtual Observatory - India. Ajit Kembhavi Inter-University Centre for Astronomy and Astrophysics Pune, India. A collaboration between IUCAA and PSPL, with a grant from the Ministry of Communications and Information Technology. The City of Pune. IUCAA.

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virtual observatory india
Virtual Observatory - India

Ajit Kembhavi

Inter-University Centre for Astronomy and Astrophysics

Pune, India


A collaboration between IUCAA and PSPL,

with a grant from the Ministry of Communications and Information Technology

the alliance
The Alliance

Members of the IVOA

the data avalanche
The Data Avalanche
  • An increasing number of telescopes and large area detectors are producing immense amounts of data through imaging and spectroscopic surveys.
  • Terabytes of data are now available, and Petabytes will soon be available from frequent all sky imaging.
  • Vast databases are also being produced through simulations.

Data Storage and Retrieval

The Astronomer

Vermeer 1632-1675

The Library of Alexandria

3rd Century BC

wavelength coverage
Wavelength Coverage
  • 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.
virtual observatories
Virtual Observatories
  • Manage vast data resources and provide these on-line to astronomers and other users.
  • Provide tools for data analysis, visualization and mining.
  • Develop interoperability concepts to make different databases seamless.
  • Empower astronomers by providing sophisticated query and computational tools, and computing grids for producing new science.
ivoa technology initiatives
IVOA Technology Initiatives

The IVOA has identified six major technical initiatives to fulfill the scientific goal of the VO concept.


REGISTRIES: These collect metadata about 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 or astronomical tables.
vo india projects
VO-India Projects
  • VOTable Parser in C++; Streaming data
  • Web based FITS browser
  • VOPlot
  • Plots and Statistics for VIZIER and Aladin
  • GALics data bases
  • Data mirror sites
  • Scientific data mining
  • Applications beyond astronomy
  • This is a new data exchange standard produced through efforts led by Francois Ochsenbien of CDS, Strasbourg and Roy Williams of Caltech.
  • VOTable is in XML format. Physical quantities come with sophisticated semantic information.
  • The format enables computers to easily parse the information and communicate it to other computers.
  • Federation and joining of information become possible and Grid computing is easier.
  • VOTable parsers have been developed in Perl, Java and C++.
  • Enhancements and extensions are being considered.

Streaming Parser

Non-streaming Parser


Project Design



Link Collection


Field Collection













the voplot collaboration
The VOPLOT Collaboration

Visualization and simple statistics of catalogue data. Integration with sky atlases.

the voplot collaboration1
The VOPlot Collaboration
  • The idea for VOPlot was developed through a discussion between VO-I and CDS.
  • VOPlot was developed by PSPL and IUCAA and was integrated into Vizier with the help of CDS.
  • It was then decided to integrate VOPlot with Aladin, an interface was agreed on, and the integration is now complete.
  • The collaboration was carried through a few short visits, phone calls and E-mail.
  • Main persons: Sonali Kale et al (PSPL), Pierre Fernique and Francois Ochsenbien. (CDS).


fits manager
FITS Manager

View, create and add to FITS files

Convert to other formats


votable java streaming writer
VOTable Java Streaming Writer

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

excessive memory.


fast computing
Fast Computing
  • Four Alpha Server ES-45 machines
  • Each with 4 processors Alpha 21264C
    • RAM 3 x 8 Gb + 12 Gb
  • Fast, Low latency interconnect
    • Memory channel Architecture (MCA)
  • 1 Tera-byte SCSCI storage
  • Trucluster clustering environment
  • (Tru64 Unix, DecMPI, openMP)
high volume storage
High Volume Storage

Raid 5, 4 Terabyte


IUCAA HPC Facility Hercules

HPC Team :

Sarah Ponthratnam

Sunu Engineer

Rajesh Nayak

Anand Sengupta

Co-proposed by :

Ajit Kembhavi

T. Padmnabhan

Tarun Souradeep

  • Four Alpha Server ES-45 machines
  • Each with 4 processors Alpha (21264C)
    • 1.25 GHz clock speed
    • Cache on chip: 64 Kb –I, 64 Kb-D
    • Cache :16 Mb ECC DDR
    • RAM 3 x 8 Gb + 12 Gb
  • Fast, Low latency interconnect
    • Memory channel Architecture (MCA)
  • High volume Storage
      • 1 Tera-byte SCSCI
  • Trucluster clustering environment (Tru64 Unix, DecMPI, openMP)

> 30 G flops

Preliminary HPL benchmark


Specfp2000: 1327

Linpack 1000x1000: 6847

virtual observatory india1
Virtual Observatory - India

Persistent Systems



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




Jodrell Bank


AVO Prototype Demo


Astronomy Catalogue Extractor

AVO: Aladin+SED


votable data
VOTable Data

The data part in a VOTable may be represented using one of three different formats:

  • FITS : VOTable can be used either to encapsulate FITS files, or to re-encode the metadata.
  • BINARY : Supported for efficiency and ease of programming, no FITS library is required, and the streaming paradigm is supported.
  • TABLEDATA : Pure XML format for small tables.
cvo collaborations
CVO Collaborations
  • There are three major projects at the CVO involving collaborations with other VO.
  • CVO is collaborating with the German Astrophysical VO to incorporate ROSAT X-ray data and catalogues into the CVO system.
  • CVO is collaborating with the Australian VO.to incorporate 2Qz and 2DF galaxy spectra into the CVO database.
  • CVO is an associate member of NVO and is have put in place some components of the NVO galaxy morphology demo.
science initiatives
Science Initiatives
  • Many IVOA projects have active Science Working Groups consisting of astronomers from a broad cross-section of the community representing all wavelengths.
  • The focus here is to develop a clear perception of the scientific requirements of a VO.
  • Projects within the working groups will develop new capabilities for VO based analysis.
  • This will enable the community to create new research programs and to publish their data and research in a more pervasive and scientifically useful manner.
australian vo collaborations
Australian –VO Collaborations
  • The distributed volume renderer (dvr) software, is a tool for rendering large volumetric data sets using the combined memory and processing resources of Beowulf like clusters.
  • A collaboration between the Melbourne site of Aus-VO and AstroGrid aims to develop the existing dvr software into a grid-based volume rendering service.
  • Users will be able to select FITS-format cubes from a number of "Data Centres",have the data transferred to a chosen rendering cluster, and then proceed to visualise the volume of data remotely (See Demo).
c votable parser
C++ VOTable Parser


  • Provide a library for API based access to VOTable files.
  • APIs can be directly used to develop VOTable applications without having to do raw VOTable processing.
c votable parser1
C++ VOTable Parser

Salient Features:

  • Implemented as a wrapper over XALAN-C++.
  • XALAN-C++ is a robust implementation of the W3C recommendations for

XSL Transformations (XSLT) and the

XML Path language (XPath).

  • XPath queries can be used to access the VOTable data.
c votable parser2
C++ VOTable Parser
  • Initial version

- 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.

  • Future enhancements

- Can be incorporated quickly and efficiently.

parser design
Parser Design

Class Details

  • VTable: In memory representation of a single <TABLE>

from the <RESOURCE> element in VOTable

  • TableMetaData: Contains MetaData (Fields, Links and Description)
  • Resource:Represents the <RESOURCE> element in the VOTable.
  • TableData: Contains Rows
  • Field: Representation of <FIELD> from VOTable
  • Row: Representation of <TR> from VOTable
  • Column: Representation of <TD> from VOTable
parser design1
Parser Design

API – Typical Operations

  • File Level I/O Routines
    • Open VOTable file
    • Close VOTable file
  • Table I/O Operations
    • Get number of rows
    • Get number of columns
    • Get column(field) information (column name, column number, etc.)
    • Accessing table data
parser implementation
Parser Implementation
  • Development on Windows NT 4.0 platform using VC++. Ported to RedHat Linux 7.1/gcc-2.96 with zero effort.
  • 18 C++ classes representing various elements of the VOTable format.
  • 8500 lines of C++ code written for V1.1 release
  • Project start date: April 7th 2002
  • V1.1 Release: May 31st 2002
  • Current status: V1.2 design in progress

What is in Release V1.1

  • Parser to serve as a building block for developing VOTable based applications.
  • Can be easily used by users of CFITSIO library.
  • Supports powerful XPath queries against VOTable files.
  • The first version of the VO Table parser can now be downloaded:



VOTable Parser Demo

  • Serves as a tutorial to help understand the basic APIs provided by the VOTable parser.
  • Demonstrates how to access the data and metadata elements of a VOTable file.
future work
Future Work
  • Develop APIs for writing data in VOTable format.
  • Develop APIs for supporting IMAGE data and FITS files in VOTable.
  • Enhance existing API set to allow more elaborate and flexible operations on VOTable files.
  • Support future VOTable versions.
  • Develop applications for conversion between FITS and VOTable formats.
  • The first version of the C++ parser can now be downloaded from the VO-India website


  • VOTable Details: