A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Roger W. Sinnott
Date: 2018 Nov 27, 20:08 -0500
By the way, the latest (3rd ed., 2013) of the Explanatory Supplement to the Astronomical Almanac, on pages 277-280, gives a number of methods for finding the atmospheric refraction. Along with several low-accuracy formulas, it describes a precise algorithm for calculating refraction using numerical integration. This method is written out in clear steps, like the outline of a computer program.
PS: You said "astronomer Bruce Young" wrote the explanation of Cassini's refraction model that you linked to, but it was Andrew T. Young (an esteemed astronomy professor of mine, many years ago).