AAS 197, January 2001
Session 40. REU: Instrumentation, Star Clusters and Galaxies
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

## [40.04] Photometric Monitoring of M67 with the GNAT 0.5-m Telescope

J.H. Roberts (Virginia Tech), E.R. Craine (GNAT, Inc.), M.S. Giampapa (NSO)

A long-term program of nightly observations of the solar-age and solar-metallicity, galactic open cluster, M67, was initiated with the prototype GNAT 0.5-m automated telescope in conjunction with a SITe 512 \times 512 thermoelectrically cooled CCD. The broad objective of this program is to investigate the utilization of the GNAT 0.5-m telescope for long-term projects requiring high-precision photometry. The specific, dual applications include (1) the monitoring of low-amplitude luminosity variations in solar-type stars and (2) the detection of extrasolar planets via photometric transits. These science goals require that precisions of at least a few millimags be consistently achieved and maintained. As a prelude to these kinds of programs, we obtained a nightly time-series of automated photometric observations of M67 on 24 nights during a two month period from abbreviated JD51604-JD51679. Unfiltered photometry with an integration time of 180 sec per CCD frame was performed. A total of 1,260 frames were obtained. For those frames characterized by high signal-to-noise ratios, precisions of 4-5 mmag were attained on both an intranight and internight basis. No variations that could be attributed to a photometric transit event were detected. Further preliminary results from this program will be discussed.

JR gratefully acknowledges the support of the NSF through the NSO/REU program. The NSO is operated by AURA under cooperative agreement with the NSF.