There are two kinds of Amateur Astronomers - those who possess telescopes or have access to them, and those who do not. The value of observations of amateur astronomers are discussed as well as historically known amateur astronomers.
The earliest recorded astronomical observation in South Africa or in its neighbourhood dates back to about B.C. 600. It was made by Phoenician sailors who were sent to attempt the circumnavigation of Libya or Africa by Necho, Pharaoh of Egypt, who reigned from B.C. 609 to 594. Herodotus (iv.42) records their observation as follows - ""as they sailed around the coast of Libya they had the sun on the right hand"". Herodotus was skeptical of its accuracy but to-day we regard it as the chief evidence that the Phoenicians did really circumnavigate Africa. In A. D. 1485 Diogo Cao reached Cape Cross in South West Africa. Diogo Cao was followed by Bartolomeo Diaz and Vasco de Gama.
Since Sir John Herschel published positions of 100 stars in this cluster from his micrometer observations (1834-38) a number of attempts have been made to detect differential motions of individual stars (W. C. Russell, 1872; Gould, 1882; Nangle, 1908). The only published photographic observations known to the writer are those by Gould (Cordoba Resultados Vol. 19).
The universe has been called ""The Realm of the Nebulae"". This name has been proposed by E. Hubble; it is the title of the book in which he has descriptionbed the results of the observations made with the Mount Wilson telescopes. This name expresses the fact that the units with which the universe is built are the nebulae: systems each of some thousands of millions of stars and of clouds of gas or dust. Such is our own galaxy and the similar systems which surround it called extra-galactic nebulae or galaxies. The objects which are loosely termed nebulae can be divided into three main classes, the diffuse galactic nebulae, the planetary nebulae and the extragalactic or spiral nebulae.
Besides the interest taken by astronomers in measuring the size of the earth, they have as mathematicians and in other ways assisted the general science of geodesy by their contributions to map projections or the depicting of an oblate spheroidal earth surface on a plane sheet of paper, and by their assistance generally in respect of improvements to instruments, clocks, etc.