WHAT: Very Large Telescope Interferometer (VLTI)
WHERE: Paranal Observatory, Atacama Desert, Chile
WHO: European Southern Observatory
WHY: To break through astronomy's glass ceiling - the 10-meter telescope - and create the most powerful stargazer in the world. ESO researchers avoided the technical and financial obstacles to building a bigger single mirror by networking four 8.2-meter and three 1.8-meter scopes into an eye 20 times stronger than any standalone and 100 times more powerful than the Hubble. VLTI will help scientists verify the existence of a black hole at the center of our galaxy; study the volcanoes of Jupiter's moon Io; and search for planets in nearby solar systems.
HOW: Light beams collected by the seven telescopes are transmitted into the interferometer's 168-meter delay-line tunnel. Once inside, the beams enter an optical retroreflector - a trainlike carriage fitted with a series of movable, gold-plated aluminum mirrors that equalize the distances traveled by the beams from their respective scopes. (This allows them to be brought into focus.) The interferometer then combines the beams, analyzes their light waves, and translates the resulting data into a digital image. In the wake of successful tests last March, Paranal engineers will bring two of the four 8.2-meter telescopes online by the end of 2001. The remaining scopes will be added incrementally over the next few years.
