Fields of astronomy other than those already considered were left entirely to the amateur astronomer prior to 1939, when the Carter Observatory Board was established by Act of Parliament. The principal exception was the valuable contribution made to the calculation of cometary orbits and ephemerides by C. E. Adams. Methods developed by him are now standard practice and have even found their way quietly into artificial satellite orbit theory. In general, he was well ahead of his time in the then whole field of astronomical calculation, and undoubtedly strongly influenced L. J. Comrie, a New Zealander later destined to be a superintendent of H.M. Nautical Almanac Office, London.

In the realm of theory there has never been any personality in the country to equal A. C. Gifford (1861–1948). Intrigued by an idea of Professor A. W. Bickerton that novae were produced by the grazing impact of two stars, he spent the greater part of his life developing such a theory. Present-day knowledge finds this theory inadequate, but his work on the impact of meteors on the lunar surface as the cause of lunar craters has had a powerful influence right up to the present time. His intense enthusiasm as a science teacher and amateur astronomer inspired all those who came directly or indirectly under his influence.

There have been so many keen amateur observers that to select the most outstanding is by no means easy. In terms of highly significant contributions to the science, John Grigg (1838–1920), J. T. Ward (1861–1927), R. A. McIntosh (1904– ), and Albert F. Jones (1920– ) are well worthy of consideration. Grigg completed a small but extremely well designed observatory at the rear of his music warehouse at Thames in 1884. Among his activities he was an ardent observer of comets and discovered several. At a time when communications were difficult he also performed the remarkable feat of computing orbits and ephemerides. Ward is mostly remembered for the enormous number of telescopes and optical components constructed by him, as well as for the establishment of the Wanganui Observatory housing a fine 9½ in. refractor. In addition, however, he is the only person in New Zealand who carried out with considerable success a survey for the discovery of southern double stars. McIntosh in Auckland pioneered the study of visual meteors in the southern hemisphere, and provided sound initial knowledge on radiants. One of his major works was the study of the relationship between the Eta Aquarid meteors and Halley's Comet. Jones in Timaru, who has been active for the last 20 years, is probably the most prolific visual observer of long period variable stars that the world has ever known. In addition, he has become the most famous visual observer of the physical characteristics of comets in the southern hemisphere.