About 10 to 15 years ago I bought a so called horizontoscoop. The instrument came from Germany and was made by Tonne. The instrument is based on an Oughtred sundial and its purpose is to see how many hours of sunlight can fall on a certain spot. In a (parabolic ?) transparant body the surrounding of that spot is mirrored. When looking through the transparant body on the Oughtred dial you can directly see during what time the spot can be reached by the sunrays and during what time there will be shadow on that spot. Is this instrument still in the market and where and for what price?
Fer. J. de Vries. [EMAIL PROTECTED]
