Understanding the Signal-to-Noise Ratio: A Key to Better CCD Photometry (Abstract)

Volume 22 number 1 (1993)

Michael V. Newberry

Department of Astronomy, University of Arizona, Tucson, AZ 85721

Abstract

(Abstract only) In order to produce the best photometric measurements from CCDs, it is essential to understand how these measurements are affected by the nature of the observations and the methods employed in processing the data. An exact, mathematical description of these effects can be obtained from the so-called "signal-to-noise" equation, which characterizes the random errors present in a measurement. The author derives the complete signal-to-noise equation and carries it through to a final description for the uncertainty of a photometric measurement made against the bright background of the night sky. Perhaps the most important aspect of this equation is not what it can tell us about the uncertainty of exisiting measurements but, more importantly, how we can plan our observations and choose methods of computer image processing so as to minimize the amount of "noise," or uncertainty, in our measurements.