Last week, the fourth and final unit of the European Southern Observatorys Very Large Telescope (VLT) achieved "first light" by snapping its first image of a distant stellar gas cloud located 6,000 to 8,000 light-years away from Earth.

The fourth telescope is known as Yepun "Venus" in the language of Chiles indigenous Mapuche people. Yepun was put to the test for the first time on the evening of September 3 after a series of mechanical trials checked out perfectly. The resulting image isnt remarkably clear, but its all astronomers needed to make sure Yepun is ready to roll.

"Tonights results demonstrate that the machine is performing very well as well as the other three telescopes we already operate," said Massimo Tarenghi, manager of the VLT project, after he and his colleagues witnessed the capturing of Yepuns momentous first image.

Yepun, an 315-inch (8-meter) telescope, joins three working siblings, Antu ("sun"), Kueyen ("moon") and Melipal ("southern cross"), which have been in operation since May 1998, March 1999 and January 2000, respectively.

With the addition of the Yepun telescope, the VLT becomes one of the largest optical telescope in the world. When finally connected, the four 8-meter telescopes will have a combined light-collecting power equivalent to that of a 16-meter (630-inch) telescope.

The VLT telescopes currently work primarily in the optical range of the electromagnetic spectrum the same general range employed by the Hubble Space Telescope. They have imaged hundreds of objects in deep space, aiding astronomers quest to understand our celestial neighbors.

And in just about six months, these four observatories will be joined as one to form the VLT Interferometer, which will give astronomers the added ability to track deep-space energy emissions with astonishing clarity.

Interferometry is a technique used by astronomers to compile extremely accurate positions for energy sources out in space. The technique uses several distinct observatories, which independently collect radiation from celestial sources, bringing them together to form one clear picture.

"Our good results are giving us confidence for when we put together the four telescopes for interferometry," said Tarenghi. "The ability to achieve high resolution is not only a dream, but a reality."

Project leader Tarenghi admits that there are "severe specifications" that need to be met in order to complete the interferometry portion of the VLT project. But he remains confident that workers at the Paranal Observatory, the site of the VLT, will make headway in good time. The VLT Interferometer is currently expected to achieve first light in about six months.