Installing the VISTA mirror

The VISTA telescope's main mirror was installed under a very clear skies in the Chilean Andes.

European Southern Observatory

We live in the golden age of sky surveys. These are projects that, rather than studying a particular astronomical object, inventory a large area of sky for everything within it that meets some particular set of criteria.

The grandaddy of all such projects is the National Geographic Society – Palomar Observatory Sky Survey (POSS), created from 1950 to 1957. It photographed all of the available celestial sphere to about 22nd magnitude in red and blue light on 14-inch-square glass plates, using the Palomar 48-inch Schmidt camera. The revolutionary effects of POSS (and its extensions) throughout astronomy proved the huge value of such projects, and POSS laid the way for many other kinds of surveys to follow.

A second revolution came with digital imagers, image-analysis software, and automatic database creation — so that today's surveys (often available as images online) contain countless objects that have never been studied or even been looked at by a human eye. "Data mining" has thus become an important new branch of research astronomy: no telescope required.

All this is by way of background to a press release that we got a few days ago from the European Southern Observatory (ESO). It announces that the 4.1-meter (160-inch) mirror has been completed for the upcoming VISTA project, the Visible and Infrared Survey Telescope for Astronomy. This project will map the southern sky with new depth and resolution in the near infrared, with especial value for studies of solar systems being born, low-mass brown dwarfs, and cosmology involving highly redshifted objects in the early universe.

The mirror itself, with a deep f/1 hyperboloid shape, is the most steeply curved optic of its size ever made. The telescope is under construction at ESO's Cerro Paranal site in the Chilean Andes. It should be finished, fine-tuned, and starting work by early next year.

No one paid attention outside a few circles of astronomers. So far, the press release has failed to prompt any news article caught by Google News. But in coming years VISTA, like other new giant surveys now in the works, will surely affect everyone's view of the universe.


Image of Jim McManus

Jim McManus

April 25, 2008 at 2:28 pm

Marginally, the 8.4m mirrors on the Large Binocular Telescope in Arizona are f/1.14.

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