Dear Tony, thanks for your reply. For me this project has many dimensions. It is a sundial for my girlfriend's family. And it is a scientific project. And it should look fine. And it should help people who want to know time or even like thinking about their environment. The second point (mathematics) does not allow me to follow your very good idea of projecting. My target accuracy would get hurt by this.
Dear Frank, thank you as well for your long reply. I agree that the wall is not flat. But I do not have any idea how to check and later describe this in accuracy. I made a little computerprogram to calculate everything. This program can handle the 1.6° deviation of the facing west sundial and it could even handle asloped flat walls. And I could improve the script to handle non-flat (not plane) walls, if you give me a (simple) mathematical description of it. You described your very applied approach to the sundial you made: you just measure where the shadow is at a certain point in time. Please don't get me wrong: I am very happy that you answered and gave so many good comments. I am impressed by your procedure and your sundial (or the image I saw of it!), this is really great. I am just facing some outer restrictions that prevent me from following your path. Eg I agree that summer would be a better time, but the scaffolding will be removed after xmas, so I have to hurry (and freeze). One last question to _all of you_: The size is 5.2m x 4.2m. How thick sould I make the analemas? The sundial can be seen from roughly 150m distance. Now I made it 2.5cm and the annotations (14, 15, 16 etc) have a height of 20cm. What do you think? Thanks, Thomas --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
