A screen grab of the WorldWide Telescope in action. Insets: Microsoft's Dr Curtis Wong and the late Dr Jim Gray.

A free program launched today will effectively turn every computer that downloads it into a mini-planetarium capable of displaying high resolution images of millions of stars, planets and other celestial bodies.

The project, called the WorldWide Telescope (WWT), is the result of several years of hard labour by a small team at Microsoft Research, the software company's key R&D centre.

It has drawn lavish praise from some of the world's leading space scientists and educators, including Dr Roy Gould of the Harvard-Smithsonian Centre for Astrophysics.

"Galileo's telescope started to give us views of the universe that no one else had seen before and we started asking what was out there and why. And I think the WorldWide Telescope is going to do the same thing for the rest of us," he said in a telephone interview.

"In terms of pushing the envelope, this really pushes the envelope."

The program works in the same way as many online mapping tools, allowing users to zoom around on an interactive canvas combining images and data drawn from the world's leading astronomical research organisations.

At launch, the WWT has access to 12 terabytes of data - enough to fill the equivalent of 1.2 million books. But like the universe, this will expand as new images are added.

Dr Gould believes the WWT will give amateur astronomers and even complete novices an opportunity to assist the scientific community in furthering their research.

"This is going to change our relationship with the night sky in a significant way," he said.

WWT is being offered without strings attached from today as an educational tool and was created to honour the memory of the late Dr Jim Gray, a leading Microsoft computer scientist who was lost at sea in 2007.

Dr Gray believed that the vast amount of space data being collected would change astronomy from being an observational science into a computational one, said Dr Curtis Wong, a leading Microsoft research scientist and the head of the WWT project.

With the growth of the internet and the increasing processing power of standard computers, Gray could see the internet becoming the platform for a worldwide virtual observatory which anyone could use.

A key feature of the program is the ability of users - any user, not just the experts - to create rich media tours to showcase features found on the WWT database.

For instance, one of the tours takes you across the Martian landscape using images captured in the Mars Rover program.

"For millennia ... every different culture has their own story about the heavens," said Dr Wong in a telephone interview. "The WorldWide Telescope is an opportunity for people to create and share those stories."

The Microsoft project is being launched almost nine months after Google rolled out its Google Sky service, a layered map of astronomical images that its part of its Google Earth program.

But there is no sense of a space race between the two giants of the technology world. Both projects have no commercial application and exist as public service tools.

Dr Wong would not be drawn on making comparisons between the two although it has been previously reported that the WWT packs in much more data and imagery than its Google counterpart.

The WWT comes as a 20MB download and is available from the WorldWide Telescope site. The program only works on the Widows operating system.