Karon, although sundials usually show the lines of theoretical sunrise and sunset (that is when the sun height is exactly zero degrees), Orologi Solari can draw the lines of the true sunrise and sunset (that is when the center of the sun crosses your true horizon) taking into account mountains and hills. This is obtained by means of altitude data that NASA made available from the shuttle SRTM mission. An example of such a dial, made by Renzo Righi, is shown in the attached picture. To get more information please have a look at http://digilander.libero.it/orologi.solari/download/srtmENU.pdf and http://digilander.libero.it/orologi.solari/download/horizonENU.pdf An article on this subject should be published soon by the italian magazine "Gnomonica Italiana" and by "The Compendium". Ciao. Gian
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