Astronomical Refraction: Computational Method for All Zenith Angles.

It is shown that the problem of computing astronomical refraction for any value of the zenith angle may be reduced to a simple, non-singular, numerical quadrature when the proper choice is made for the independent variable of integration. The angle between the radius vector and the light ray is such a choice. The implementation of the quadrature method is discussed in its general form and illustrated by means of an application to a piecewise polytropic atmosphere. The flexibility, simplicity and computational efficiency of the method is evident. (Author)
Sponsored in part by Grant NSF-GP-26495.