A team of European researchers has employed a new research technique called "virtual astronomy" to mine vast unexplored telescope data with a new computer software program.

The first result of the technique is a claim that a recently discovered space rock, called 2001 KX76, is larger than previously thought. In fact, it may be the largest known, eclipsing the asteroid Ceres for that title.

But other astronomers, while appreciating the value of the technique and even saying it may be the wave of the future for astronomy, said it's too soon to officially hand over Ceres' crown.

Ceres was the first asteroid discovered, in 1801. It is big and relatively close, which is why it was found first. It is roughly 590 miles (950 km) wide and lies in the main asteroid belt between Mars and Jupiter.

Astronomers are no strangers to studying old photographs, but the newly reported work employs a software program that speeds up the archival digging. The program, called Astrovirtel, operates at the headquarters of the European Southern Observatory in Germany.

A team of German, Finnish and Swedish astronomers, announced the initial results on Thursday.

By combining recent observations with data going back to 1982, the researchers derived a more accurate orbit for 2001 KX76 because they could effectively see it move through time, thereby studying a larger section of the orbit's arc. Determining the distance to a single point of light in space, on the other hand, is extremely difficult.

This improved orbit estimate allowed them to generate a more accurate distance estimate for the object, now put at roughly 4 billion miles (6.5 billion km). Based on this, the group said 2001 KX76 has a diameter of 745 miles (1,200 km) and possibly larger.

"Plausible but not proven," said David Jewitt, a University of Hawaii researcher.

Jewitt's caution stems from the fact that the new diameter estimate is based on how much sunlight the asteroid reflects vs. how much it absorbs. This figure, called albedo, is not known with certainty for any asteroid or Kuiper Belt Object, let alone those as far away as 2001 KX76. Different objects have different compositions, and some absorb sunlight more than others.

The new study was led by Gerhard Hahn of the German Aerospace Center. Hahn agreed that the albedo is the crucial data needed to derive an asteroid's diameter.

"This is not known," Hahn told SPACE.com. "And we did only make a (as we think) reasonable assumption."

Hahn and his colleagues applied the albedo that Jewitt had determined for Varuna -- 7 percent. A smaller albedo, 4 percent, had previously been assumed for all Kuiper Belt Objects. Applying this figure would yield a larger diameter.

Robert Millis, who led the team from the Lowell Observatory in Arizona that discovered 2001 KX76, said the new work was done by competent astronomers and supports his team's case that this is a large object.

But Millis said much more research needs to be done before a diameter can be declared.

"They have not measured the diameter of this object," Millis said in a telephone interview. "What they have done is they've improved its orbit, and that's an important thing to have done."

Millis said the diameters of distant space rocks won't be known with certainty until future space-based observatories are devoted to accurately measuring their albedos.

"Until somebody ... actually measures the albedo and doesn't assume the albedo, we can't with any great accuracy determine the diameter," he said.

Meanwhile, Jewitt said the method of the study may be the wave of the future. With telescope time difficult to come by, old photos can often be mined for objects that were not part of the original study. And there are a lot of old astronomical photos lying around.

"Many people think that so-called virtual astronomy is going to be the next big thing," he said. "The idea is that, in the future, certain kinds of science will be done by digging into huge databases using intelligent algorithms instead of going directly to the telescope as we do now. What that will do is open up the time domain of astronomy: we'll see everything that moves or varies in any way."

Arno Gnädig, a German amateur astronomer who worked with Hahn on the new study, said the new technique should open the skies to more researchers. In fact, he did some of the new calculations on his home computer.

"The Web and the access to virtual observatories means that amateur astronomers -- located far from any real professional telescopes -- can also make important contributions," Gnädig said.

Hahn is now leading a broader effort to improve the size, distance and orbit measurements of asteroids in the main Asteroid Belt, some of which could ultimately be determined to be potentially threatening to Earth.