W. M. Smart – författare

In many of the sciences there is no means of ensuring absolute accuracy in the measurement of a particular quantity. The difficulty can to some extent be overcome by making several independent sets of observations and by combining these to give the most probable result. This done, the degree of precision of the calculated value can in its turn be assessed. It is seldom a straightforward matter of taking the average reading, and in many cases a knowledge of the theory behind the methods of combining observations becomes essential. It is this knowledge that Professor Smart provides.

This well-established textbook gives a general but comprehensive introduction to positional astronomy. Originally based on the author's lecture courses at Cambridge University, it is intended primarily for undergraduates, but, due to its comprehensive nature, it is a very useful reference text for research workers in many branches of astronomy and space physics. The author considers the night sky as the celestial sphere and powerfully exploits the methods of spherical geometry. Most problems in which the precise determination of a heavenly body's position in the sky is important are considered in theoretical detail, and the necessary formulae are derived to a precision that is sufficient for all but the most specialist purposes. The present revision has ensured that the terminology and treatment correspond precisely to current astronomical practice. A guiding principle has been to re-establish compatibility with the Astronomical Ephemeris and, to a lesser extent, with the fuller explanations of the Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac. Fairly frequent comments added to the text indicate the sometimes modified relevance of the subject matter to modern astronomy. A number of additional exercises help to illustrate the new material.