Figure: The transit of TrES-1

The transit of TrES-1, also known as GSC 02652-01324 or 2MASS 19040985+3637574, was discovered in August of 2004 and was the first to be detected by the transit method. The finding was made by an international team of astronomers using a 4-inch Schmidt telescope, named STARE and stationed in the Canary Islands, and mostly off-the-shelf equipment. STARE belongs to a network known as the Trans-Atlantic Exoplanet Survey (TrES, pronounced "trace"), with the other two locations being situated at Lowell Observatory and on Palomar Mountain. The instruments making up the remaining TrES network include 4-inch camera lenses that sit on mounts using SBIG autoguiders, where the image is focused onto CCD cameras. The equipment used is akin to that available to amateur astronomers (Naeye 2004).

TrES-1 is located in the constellation of Lyra at a location 500 light-years away from us here on Earth. The K0-type star normally shines at a magnitude of 11.8. The planet, meanwhile, is about 0.75 Jupiter mass and has a diameter about 8% larger than Jupiter. The planet orbits its host star every 3.03 days and is about 0.04 astronomical units away. Transit depth of TrES-1 is about a 2% dip in magnitude (Alonso et al. 2004; Naeye 2004).

The discovery of TrES-1 was announced by professional astronomers on August 24, 2004. An impressive 8 days later, a transit of the same system was confirmed by an amateur astronomer in Belgium, Tonny Vanmunster (AAVSO observer VMT), as reported in an online Sky & Telescope article. Vanmunster used his Celestron C-14 telescope and an SBIG ST-7XME CCD camera (without filters) at his private observatory. The event was captured in real time using software he had written. As predicted, Vanmunster's transit took place on September 1, 2004 at 21:13 UT and lasted about 3 hours, where the brightness of the star dipped by about 0.03 magnitudes (Naeye 2004).

David Charbonneau, coleader of the team to discover TrES-1 and of the Harvard-Smithsonian Center for Astrophysics commented, "I'm thrilled that this confirmation has come from an amateur. But perhaps we shouldn't be too surprised. He did, after all, have a telescope with an aperture three times larger than ours!" (Naeye 2004)

It is reported that a handful of other amateurs independently confirmed the transit as well: Ondrej Pejcha, Pertti Paakkonen (PPK), Samo Smrke & Nicolaj Stritof (SNJ), Robin Leadbeater, Joe Garlitz (GJP), Ron Bissinger, and Bruce Gary (GBL).

Credit: Tonny Vanmunster

http://aavso.org/vstar/vsots/fall04.shtml