The Double RefractorProfessor Nils Dunér's efforts to have a modern photographical telescope in Uppsala was successful in 1890 when the Swedish parliament granted a sum of 63 500 SEK for a new telescope and the construction of a new dome at the Uppsala observatory. The telescope was mounted in late 1892 in the new dome, and the first test plates were obtained in early 1893.
The visual part (D=36cm) and the photographic part (D=33cm) of the optical system (f/15) are manufactured by Steinheil in Munich and the mechanics by Repsold in Hamburg.
The refractor was used for research purposes into the 1960's, in the latest years mainly for astrometrical studies of brighter double stars, a project that had been going on since the beginning of the century.
The instrument has produced thousands of photographical plates and spectral plates since 1893, now a part of the observatory's plate archive.
Today the telescope is used to show the brighter objects that are suitable, for all the groups from the general public that visit the observatory each year. It is also used by Uppsala Amateur Astronomers - UAA - for mainly planetary observations.
Professor Nils Dunér correcting the hour angle (~ 1900)
Students (Uppsala student caps) observing (~ 1900)
The telescope today with
Dunér's spectrograph mounted
on the photographic part