A Domeless Coudé Refractor for Solar Work

Abstract
To avoid the image-deteriorating heat flow around the telescope, a new type of solar Coudé refractor (aperture 35 cm, equivalent focal length 15 m) has been developed which does not need a dome but which is nevertheless protected from the wind and weather. This is achieved by enclosing the telescope proper within a second tube which is independently mounted and guided. The construction of the instrument guarantees free circulation of air around the prime objective.