J. G. Hofmann, Parigi, 1870
mm 650 x 100 x 100

In this so-called direct vision spectroscope five flint and crown glass prisms are combined so that the entering light rays leave the prisms in nearly the same direction. The spectroscope was used for the first time in 1870 for the observation of the Sun’s total eclipse in Sicily. The resulting combination of telescope and spectroscope was named telespettroscopio. It was mainly used for the study of the solar chromosphere.