An accurate method for computing atmospheric refraction

This paper describes a method for computing atmospheric refraction that is simple, highly accurate, and usable for wavelengths lambda lambda 3000-10,000 Angstrom. When compared with the Refraction Tables of the Pulkovo Observatory [Albalakin, V. R. 1985 (Leningrad, Nauka)], the computed and Pulkovo refractions are in extremely good agreement (similar to 10 mas or better) for zenith distances under 65 degrees, and at a zenith distance of 75 degrees, the agreement degrades to about similar to 150 mas. Moreover, this refraction is easy to compute, since only knowledge of the meteorological conditions at the observing site (e.g., ambient temperature, atmospheric pressure, and dew point or relative humidity), the apparent zenith distance of the object being observed, and the location of the observing site relative to the Earth's geoid are needed for its calculation. Because of its simplicity and high accuracy, the refraction presented in this paper is well suited for programs where huge amounts of data need to be processed quickly to star positions or for accurately setting automated telescopes. In addition, the refraction for a given telescope passband will differ in a way dependent on the spectrum of the object being observed. This paper describes how a mean refraction, weighting the selective refraction over the passband, can be computed.