Major telescopes from Lord Rosse to about 1980

Abstract

In Chap. 1 a brief account of the development of the reflector up to William Herschel was given. From 1800 to about 1840, the pendulum of rivalry between the reflector and the refractor swung back in favour of the refractor through the epoch-making work of Fraunhofer in the development of optical glass and its systematic application to refractors such as the Dorpat refractor of aperture 24.4 cm. The fact that refractors of relatively modest size were able, in spite of the limitation of secondary spectrum, to compete with or even excel reflectors with apertures up to 1.22 m (Herschel) was a measure of the two great weaknesses of the reflectors of the time: the poor efficiency through low reflectivity and the problems of mechanical manipulation in such sizes.