tower telescope

an astronomical instrument with a vertical (vertical telescope) or inclined fixed optical axis; it is used mainly for investigating the sun. (See Figure 1.)

Figure 1. Diagram of the solar tower telescope of the Crimean Astrophysical Observatory of the Academy of Sciences of the USSR: (1) coelostat, (2) auxiliary mirror, (3) main mirror, (4) slit of double-ray spectroheliograph, (5) slit of spectrograph.

In the tower telescope of the Crimean Astrophysical Observatory of the Academy of Sciences of the USSR, the rays from the heavenly body are directed by the coelostat (1) and the auxiliary mirror (2) onto the main mirror (3) and then by a system of mirrors to the slit of a double-ray spectroheliograph (4) or of the spectrograph (5). Spectral and magnetic investigations of the photosphere and chromosphere and sunspots, faculae, flocculi, chromospheric flares, and other solar phenomena are made using a tower telescope. The first tower telescope was built in 1908 at the Mount Wilson Observatory (USA). The largest tower telescope (at the same observatory) gives an image of the sun with a diameter of 43 cm; the height of the tower is 45 m.