MICROSOFT THIS week took the wraps off an astonishingly vast visual guide to the universe that is powered by some of the world's best astronomy telescopes.

Developed over the past six years in the technology giant's research division, Microsoft is releasing the application free of charge, in part to show off its Visual Experience Engine.

The engine provides smooth panning and zooming that allow viewers to focus on a particular planet or cluster of stars without abandoning the scale of the area surrounding it.

"It's gorgeous, that's the main thing," says curator Laura Danly of the Griffith Observatory in Los Angeles.

"This is a labour of love and a work of art. It is really deeply thought through."

Microsoft principal researcher Curtis Wong says the visual engine is more of a means to a desirable end than an end in itself.

"We develop technologies that can help shape future Microsoft products," he says.

"In my group, what we try to do is build something with some larger benefit to the public at large."

Available as a free download from www.worldwidetelescope.org, the programme works, as one might suspect, only on computers using the most recent Microsoft operating systems, Windows XP and Windows Vista.

Apple computers with those versions of Windows can also support the software, which performs best on machines with strong graphics capabilities.

Astronomers and educators say the WorldWide Telescope is important because it amalgamates so much data - visual and verbal - and allows users to examine space as it appears in natural light or with infrared, X-ray and other views.

"Nasa operates a number of telescopes that are daily sending back spectacular images. But if you have a single tool that will let you get to all the images and see how they relate in context, it becomes an incredible opportunity for investigation and exploration," says California Institute of Technology astronomer Robert Hurt, who works on Nasa's Spitzer Space Telescope.

"One of the nice things about WorldWide Telescope is that it has almost a cinematic representation of the data," Hurt says. Unlike Google's space view, Google Sky, "the interface was designed from the ground up to be optimised for sky navigation".

Griffith's Danly agrees, saying that the Google version "is not as ambitious a project".

Besides moving in or out to peer at an object, Telescope viewers can choose perspectives from different locations on earth. And they can look at the universe as it appeared far in the past, turning the programme into something of a virtual time machine. Hit fast forward, and you can watch Jupiter's moons spinning as they orbit the planet.

All of which can be a bit intimidating - space is, after all, pretty big - and the navigation takes some getting used to.

But WorldWide Telescope also offers guided tours, in which experts give slide shows on areas of interest. Users can create and share their own slide shows, the best of which will be offered up to all others on the system.

Wong, who grew up in Los Angeles, says he expects the project to be especially popular with students.

"I didn't really see the stars well until I was in high school" because of all the ambient light in the city, Wong says.

"About 70 per cent of US kids live in large urban areas, and I doubt if any of them have seen the Milky Way.

"This is my way of showing them." -