TUCSON — The first asteroid glimpsed by astronomers before it crashed into Earth was spotted with a couple of refurbished telescopes hooked up to some digital cameras by the Catalina Sky Survey.
The closest thing to an Earthlike exoplanet was found recently with a telescope at Whipple Observatory that an avid amateur might have in his backyard.
From that same ridge in the Santa Ritas, an astronomer has discovered 13 exoplanets orbiting distant stars with the kind of telephoto lenses you would use to snap pictures of a high school football game.
Giant land-based telescopes and space missions gobble up most of the money available each year for astronomical exploration. But innovative astronomers are proving that you don’t need a multibillion-dollar orbiting telescope to find planets or even save the world.
Lately, they have been making headlines and making the point that the worth of a discovery is not directly related to the size of investment.
Gaspar Bakos started his planet search with a $350 Nikon telephoto lens from a used-camera store in Manhattan.
His current arrays — including four HAT telescopes at Whipple Observatory on Mount Hopkins in Arizona — are a bit pricier. Once you add the fancy digital technology and mounting hardware, each telescope costs about $50,000.
The design, developed by Bakos and three amateur astronomers in Hungary, still employs a relatively modest telephoto lens, hooked up to a CCD camera and set on a movable, robotically controlled mount.
They scan the night sky in a wide field, searching for the periodic dimming of stars, signs that a planet is passing.
Bakos, an astronomer with the Harvard-Smithsonian Center for Astrophysics, has now found 13 planets — mostly big balls of gas. Some demonstrate novel properties. One, bigger than Jupiter but with half that planet’s mass, has been called “the puffy planet.” It would float in water, if you had a very large bathtub.
Bakos’ program, now at sites in Arizona and Hawaii, is called HATnet, the Hungarian-made Automatic Telescope network. Bakos was honored as one of Popular Science’s “Brilliant 10” in 2007 for his accomplishments.
Astronomers such as Bakos and Harvard-Smithsonian colleague David Charbonneau, who developed the moderately priced MEarth array on Mount Hopkins, are good “advocates for small telescopes,” said astronomer Emilio Falco, science director for several programs at Whipple Observatory.
Falco, who helped build and provides technical support for the HAT and MEarth arrays, said “there is still a trend toward the larger telescopes, with all the funding diverted to these huge projects. However, as Gaspar and other groups have shown, you can do a lot with these small telescopes.”
Charbonneau pioneered the technique of searching for planets around distant stars by measuring the light lost when the planet orbited or transited in front of the star.
Then he got the idea to use an array of off-the-shelf telescopes to search the sky for such reductions in the light emitted by nearby stars. He chose 2,000 of the smallest ones, known as M stars, and began to look for rocky planets similar to Earth but about twice its size.
He’s searching for “earths” around M stars, hence the name MEarth. It is pronounced “mirth,” said Charbonneau, “because it makes us happy.”
Eight of MEarth’s telescopes sit in a boxcar-sized enclosure known as “the shed” on Mount Hopkins. They click automatically to life when the shed roof rolls back at twilight, feeding data to Cambridge, Mass., where Charbonneau and his colleagues look for signs of a transit.
Finding a rocky planet in a habitable zone near its star would be a coup. Most of the 400 exoplanets discovered so far are big gassy giants like Jupiter.
Charbonneau said he chose his targets to match the limits of his viewing technique. Did such things exist? He didn’t know, but he expected they did and predicted it mathematically.
Sure enough, he recently announced a startling discovery in the scientific journal Nature — the most Earthlike planet discovered so far.
It’s a little close to its sun and a bit too hot for life as we know it, but it’s made of rock and water and has an atmosphere.
Not a bad find for an $8,000 telescope with a 16-inch mirror.
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Astronomers with the Catalina Sky Survey adopted an age-old marketing strategy to reduce the price of their science — volume, volume, volume.
The group, based at the University of Arizona, refurbished two of the Steward Observatory’s outmoded telescopes on Mount Lemmon and Mount Bigelow in the Santa Catalina Mountains and began clicking away at the night sky six years ago with digital cameras, feeding a computer program that looks for moving objects.
With those relatively modest 60-inch and 28-inch telescopes, they quickly became the world’s leader in discovering NEOs, near-earth objects that could crash into our planet.
They counted 565 in 2008 and will better that record in 2009, using an annual budget from NASA of $1 million.
“We are the Wal-Mart of astronomy. Actually, we’re the Dollar Store,” said Sky Survey Director Ed Beshore.
“If you figure a cost per asteroid, our price keeps going down,” Beshore said.
In 2008, the year Catalina Sky Survey gained fame by predicting the path of a meteor that crashed in Sudan, the price per asteroid was $1,758.
And — as they say in the infomercials — that’s not all.
The Catalina Sky Survey is now wholesaling its unexamined data to other astronomers. A pilot program with CalTech recently yielded 877 sightings of peculiar objects — active galactic nuclei, stellar flares, supernovae and optical transients.
Now the folks at Caltech have snared a grant to combine those data with results from Catalina’s Southern Hemisphere observatory at Sliding Spring in Australia. Then they plan to put real-time images from the three telescopes online, along with a library of the same portions of the sky taken in past viewing. The data will be made available for searching to armchair astronomers everywhere.
It is a low-budget version of the type of “synoptic” sky survey envisioned by more grandiose astronomical endeavors, such as the $390 million Large Synoptic Survey Telescope.
The limits of cheap
None of these astronomers argues for an end to the big telescope projects. In fact, most of their discoveries must be verified by bigger and better telescopes.
Charbonneau, for instance, has partners in his “super Earth” search who used a giant telescope in Chile to verify his discovery. To learn more about it, he has applied for time on the Hubble space telescope, which is expected to burn through about $6 billion in its 10 years of operation.
Falco, meanwhile, has been busy verifying HAT discoveries on two larger scopes on Mount Hopkins.
“The immediate next step is to use our 1.2 meter, do follow-up to refine the light curves — the variation of brightness that gives you the transit measurement,” Falco said.
Then he uses a nearby 1.5-meter telescope that is equipped to do spectroscopy to “get a basic description of the system.”
Then it’s on to the twin 10-meter Keck Telescopes atop Mauna Kea in Hawaii.
“That’s when you hit the jackpot. You get exquisite detail,” he said.
At a price. Those Keck twins cost $200 million to bring into the world.
Information from: Arizona Daily Star, http://www.azstarnet.com