The first working version of a "one-stop shopping" service for solar data is now on line, giving scientists a much easier way to search for data on specific solar phenomena and even to confirm the results of earlier research.

"The Virtual Solar Observatory or VSO makes it possible to access data from multiple sources, even ones you didn't know existed, at one fell swoop" said Dr. Joseph B. Gurman of NASA's Goddard Space Flight Center in Greenbelt, MD.

The VSO will be discussed in two different papers to be presented at the Fall 2004 meeting of the American Geophysical Union in San Francisco on Tuesday morning, Dec. 14.

Gurman is the project manager for the VSO. Dr. Frank Hill of the National Solar Observatory in Tucson, AZ, is the principal investigator. The Association of Universities for Research in Astronomy operates the National Solar Observatory under a cooperative agreement with the National Science Foundation. Other members of the VSO team are at Stanford University, Montana State University, and Southwest Research Institute.

"We have folks lining up to provide their data through VSO," Gurman continued. At the VSO's core are decades of data and images from the National Solar Observatory Digital Library (ground-based solar telescopes) and NASA's Solar Data Archive Center (spacecraft observations), which is being transformed into the VSO. Other data services accessible in this initial release are: Stanford University Helioseismology Archive, Owens Valley Radio Observatory, Observatoire de Paris-Meudon, Montana State University, and the High Altitude Observatory. Most of the data are synoptic, covering the entire solar disk over long periods of time, but the collection may grow to include more high-resolution observations that focus on small parts of the Sun.

Like the nighttime National Virtual Observatory, the VSO does not hold all solar data, but works from metadata, that is, information about information held at the various archive sites. The VSO automatically sends a user's query to databases held at many sites, all over the Internet. Those sites search in parallel, and the VSO packages and delivers their answers to the user who can then refine the search or use links to access the data directly from the data providers.

"The VSO puts together fifty different archives of solar data and allows solar physicists to access it from a single database without having to learn all fifty databases," Hill explained.

Gurman credited Hill as "the driving force" behind the VSO effort. The idea emerged after Hill had surveyed papers in the journal Solar Physics and determined that a third of the papers worked from three or more on-line data sources. Hill realized that improving access to the data "could enable new kinds of science," Gurman continued. Building on a prior concept known as the "Whole Solar Catalog," Hill started the VSO with a "birds of a feather" working group meeting at the American Astronomical Society's Solar Physics Division meeting at Lake Tahoe, NV, in 2000. Gurman also credited NSO's Igor Suárez-Solá for developing the user interface and parts of the search engine. Other major contributions were made by Karen Tian at Stanford, Joe Hourclé at Goddard, and Alisdair Davey at Southwest Research Institute in Boulder, Colorado (formerly with Montana State University). Scientific input has come from Drs. Piet Martens of Montana State University and Richard Bogart of Stanford University.

The VSO has several search options including time, instruments, and spectral range. A scientist could ask the VSO to provide all the data that were collected during the large flare events of Oct. 29, 2003, or specify just the vector magnetograms (showing magnetic field strength and direction) from NSO's SOLIS instruments and the radio data from the Owens Valley radio telescopes. The VSO will return links to the data and will store the list, like an on-line store's shopping cart, for future reference. Gurman and Hill hope that scientists publishing papers based on VSO searches will include links to their data shopping carts so other scientists can call up the same data and reanalyze to confirm or challenge the findings, or push the findings into new areas.

"This will let the scientists do more science and less data culling," Gurman said.

The VSO is open to anyone, he continued, and anyone can make data sources available. "It can be as simple as a file server or a database manager that responds to queries," he added. No valuations or rankings will be placed on the data. "It's a marketplace where people will rapidly determine which data are good."

Links: http://virtualsolar.org/

Fall 2004 AGU papers dealing with current and planned use of the VSO are: STEREO in the Virtual Solar Observatory Context, J.A. Hourclé, et al (SH21B-0413)

Solving Science Use Cases that Relate to the Sun and Heliosphere with EGSO, R.D. Bentley, et al (SH21B-0415) Doing Science with the VSO: Signatures of CME Initiation, A.R. Davey et al (SH21B-0414).

Both Gurman and Hill will be at the AGU conference.

Joseph B. Gurman, Facility Scientist, Solar Data Analysis Center, NASA Goddard Space Flight Center, Greenbelt, MD (gurman@gsfc.nasa.gov; 301 286-4767) or Frank Hill, National Solar Observatory, Tucson AZ (hill@noao.edu, 520-318-8138)