English: Double refractor made by Zeiss in 1908, consisting of a photographic reafractor with 210mm aperture and a visual refractor with 180mm aperture. Both instruments have a focal length of 3400mm. This instrument was first used by König in Vienna, and was relocated to the Štefánik Observatory in Prague in 1928, where it is still in use today.
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{{Information |Description={{en|1=Double refractor made by Zeiss in 1908, consisting of a photographic reafractor with 210mm aperture and a visual refractor with 180mm aperture. Both instruments have a focal length of 3400mm. This instrument was first use