But these new telescopes are expected to cost between $700 million and $1 billion just to build. Operating costs are likely to range from $70 million to $100 million a year, several researchers say.
In the United States, the choices revolve not only around which, if either, of the two projects to support.
A third, more modest US project, called the Large Synoptic Survey Telescope (LSST), also is vying for construction funds and has been on the astronomical community's priority list for the past decade. And astronomers are concerned that these big projects could siphon funds from other facilities used for important exploration that doesn't require telescopes whose light-gathering mirrors would fill nearly half a football field.
An international 'science machine'
"The science of astronomy and astrophysics encompasses a wide range of topics right now – everything from asteroids and small bodies in our solar system all the way out to the first stars forming in the early universe," Dr. Silva says. "Attacking all of those problems efficiently requires a complete suite of telescopes and instruments."
Indeed, there is a great deal of synergy between the 8-to-10-meter class of ground-based telescopes, such as the Keck Observatory on Mauna Kea, and space telescopes such as the Hubble Space Telescope, says Roberto Gilmozzi, the lead investigator for the European ELT project. "Together they are a much better science machine than either separately," he says.