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Session 54 - Ground and Instrumentation Techniques and Catalogs.
Display session, Wednesday, June 12
Tripp Commons,

[54.09] Limits to the Precision of Differential Stellar Photometry

K. Janes (Boston Univ.), J. Heasley (Univ. of Hawaii)

Modern CCD camera systems can be made sufficiently stable that the limits to photometric precision are effectively set by Poisson statistics and by external instrumental and atmospheric conditions. Tests with available data sets demonstrate that frame-to-frame differences from mean differential magnitude measurements can be reduced to levels substantially smaller than 0.001 magnitudes over time scales of many minutes and angular scales of several arcminutes, even under marginal photometric conditions. With a sufficiently large telescope, scintillation and other short-term atmospheric fluctuations can be reduced to insignificant levels. Over longer time scales and larger angular scales, the results are ambiguous, suggesting the possibility of significant sources of ``1/f noise'' from unknown, presumably mostly atmospheric, sources. The prospects for photometric asteroseismology are promising and there is real potential for detecting transits of extra-solar planets.

Program listing for Wednesday