Dear Jim, I am grateful to you, and to Willy and Geoff, for various points of clarification. The key point in your comment is:
A hand with a Sun figure rotates once in a mean solar day... This at once distances the clock from an astrolabe where, properly set, you look at true solar time and not mean solar time. By not tracking true local solar time, the clock necessarily compromises the indications of any observable that depends on sunrise or sunset. So indications of the Italian hour or the Unequal hour could be a quarter of a common hour wrong even if the authorities had ignored Central European Time. Or have I missed something crucial? [It is still a splendid clock, but I want to be clear about its design limitations!] Frank --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
