Dec 2004. Sky & Telescope, pp. 18-19. Tiny Telescope Finds Big Planet. - ROBERT NAEYE. A small sky-patrol scope claims an exoplanet prize.

Excerpt: Until now, all of the 140 or so known extrasolar planets were discovered with large telescopes and cutting-edge detectors. But an international team recently turned up a "hot Jupiter" using a 4-inch telescope and mostly off-the-shelf equipment. In fact, discovery team co-leader Timothy Brown (National Center for Atmospheric Research) made the telescope's optics in the garage of his Colorado home. "I have been an amateur telescope maker a long time," says Brown. "I couldn't find the parts I needed at a reasonable price, so I built them myself."

The STARE telescope has on aperture of only 4 inches, but that was enough to find the periodic dimmings caused by TrES4. Codiscoverer Timothy Brown is pictured with the telescope. ...The discovery heralds a new era when small telescopes doing wide-field surveys will turn up many new exoplanets (August issue, page 30). Roi Alonso (Astrophysical Institute of the Canaries) discovered this one using Brown's telescope, named STARE, on Tenerife in the Canary Islands.

STARE belongs to a network known as the Trans-Atlantic Exoplanet Survey, or TrES (pronounced "trace"). The other two TiES instruments are commercial 4-inch camera lenses, located at Lowell Observatory in Arizona and on Palomar Mountain in California. At Lowell, Canon lenses sit atop a Celestron mount, and at Palomar, Leica lenses sit atop a Meade LX200 GPS mount. Both systems use SBIG autoguiders. They cast their images onto professionally made large CCDs, but Charbonneau points out that these are nearly identical to units made by Apogee Instruments for amateur astronomers.

The hard part is the data handling. The three TrES instruments precisely measure the brightnesses of thousands of stars in large patches of sky to look for subtle, periodic dips in brightness caused by planets transiting stars' disks. Alonso found the new planet, dubbed "TrES1," in a 36-square-degree field (about half the size of the Big Dipper's bowl) in Lyra containing 12,000 stars brighter than 12th magnitude. The three telescopes imaged the field every two minutes all night long for two months, and software sifted through the mass of data to detect 16 stars that showed telltale evidence of transits.

The astronomers knew that most of these candidates would be red herrings. David Latham (Harvard-Smithsonian Center for Astrophysics) and his colleagues took low-resolution spectra of the 16 stars with 60-inch telescopes and found, from the high orbital velocities, that most were ordinary eclipsing binaries. But one stood out: an obscure, 11.8-magnitude Ko dwarf named GSC 02652-01324, located 500 light-years from Earth.

Next, Alessandro Sozzetti and Guillermo Torres (Harvard-Smithsonian Center for Astrophysics) acquired superhigh-resolution spectra of the star with the 10-meter Keck 1 telescope in Hawaii. The Keck observations revealed only a low-velocity stellar wobble, indicating a planetary-mass companion. The planet has 75 percent the mass of Jupiter and orbits the star in a circular path every 3.03 days....