Tuesday, February 20, 2007

How does anyone get time on Hubble?

When I gave public tours at the Very Large Array radio telescope in New Mexico, the tourists were amazed that anybody could get telescope time, for free, if their proposal was strong enough.

Hubble, Spitzer, Chandra, and the VLA work the same way -- annually, astronomers send their best ideas on how to use each scope. Then, a jury of their peers called a "telescope allocation committee" or TAC, votes on the strongest proposals. For Hubble, about 5 proposals are rejected for every one that's accepted; for Spitzer (in part because the spacecraft is more efficient), the ratio is more like 3.5:1.

It's easy to bitch about TACs-- proposals are read hurridly, reviewers can play evil politics -- but it's hard to imagine a better method.

NASA proposals are high-stakes because the TAC awards not just telescope time, but moolah to analyze the data. Hundreds of astronomers, especially students and post-docs, are supported by Hubble alone. Thus, astronomers may apply for telescopes not because they want the time, but because they need the money.

The Hubble proposal deadline was 2 Fridays ago; the Spitzer deadline was last Friday. Thus, astronomers worldwide have been nursing proposal hangovers, and are now recovering and trying to remember what they were working on before they started writing proposals.

The public has an idea that astronomers live on mountains and look at the stars; really, we spend months per year begging for time and money, months more reducing and analyzing data, and a few weeks per year at telescopes, gathering photons. Less romantic, perhaps, but that's the real story. Any questions?

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