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D. A. Caldwell, W. J. Borucki (NASA Ames Research Center), J. M. Jenkins (SETI Institute), D. G. Koch (NASA Ames Research Center)
The NASA Ames Research Center Vulcan camera is being used to search for transits of 51-Pegasus type planets around nearby stars by viewing many stars in a large field. The camera is designed to achieve 0.1% relative photometry on several thousand stars over a period of one month, sufficient to detect transits of Jupiter or even Saturn-sized planets around a Solar-like star.
Engineering studies have been underway at Lick Observatory since October 1997. During this time there have been several major and numerous minor changes made to the system. Currently, the Vulcan system consists of a 4096x4096 pixel CCD in a 30cm focal length f/2 camera, with a 7 degree field-of-view. Images of a field are taken continuously throughout the night with 15 minute exposure times, resulting in approximately 40 Gb of data per field in a month. The data reduction is divided into two primary parts: photometry, and transit detection. The photometry portion of the processing consists of point-spread-function fitting photometry on ~4000 stars, extinction correction, and calculation of relative fluxes. Once valid light curves have been constructed, a matched-filter transit detection algorithm is run on the data.
We have analyzed data from two fields, one in Perseus and one in Cygnus. We currently achieve 0.3 - 0.5 % relative photometric precision, and have detected and begun to classify numerous eclipsing binaries and variable stars. By studying the effects on photometric precision of aperture size, background method, extinction correction, etc., we hope to improve the precision to the design goal of 0.1%.
The author(s) of this abstract have provided an email address for comments about the abstract: dcaldwell@mail.arc.nasa.gov