Our current definition of a Virtual Observatory goes something like the following:

The Australian Virtual Observatory (Aus-VO) will be a facility that provides a distributed, uniform interface to the data archives of Australia's major astronomical observatories and survey projects, to the output data sets of theoretical codes that are routinely run throughout the country, and to interactive tools and queuing systems for generating and processing both theoretical and observed data.

Aus-VO will be a key component of the International Virtual Observatory, a worldwide, decentralised facility which will link the archives of the world's major astronomical observatories and theory centres into one distributed database.

Astronomers will explore Aus-VO and the IVO using advanced data mining and visualisation tools. These tools will exploit the unified data interface to enable cross-correlation and combined processing of data from otherwise disparate sources.

Previous or alternative definitions include:

There is a range of opinion on what a virtual observatory is.

  • Some see it as a smart archive, able to pull out all the observations matching a query specified in scientific terms such as find all spectroscopic observations with R>10,000 of quasars in catalog X between 2 and 5h of RA and redshift > 1.5

Archives with this sort of capability are being developed already; SkyView?, SIMBAD and NED are well-known to most astronomers. But these are not the final word by any means. A more advanced archive, intended to allow more abstract queries like the one above is the Science Archive being developed for the Sloan Digital Sky Survey.

  • Other people envision even more "smarts"; if the archive doesn't have any data matching your criteria, it will tell you so and recommend a list of telescopes that could make the observation you require. It may even be possible for small requests to be sent directly to the observing queue of robotic telescopes.
  • Since the data is large, no one institution could house it all. This requires the VO's request processing software to be able to search globally. So a VO is an international cooperative undertaking, from the start.

In the future, this kind of access to astronomical data will be more and more common. Plans for VOs are being drawn up already; some of these were discussed at the recent CODATA 2000 meeting.

-- DavidBarnes - 05 Feb 2003