Doug, not sure if I understood it correctly, but check out San Petronio Basilica in Bologna:
[example of the influence of precession on sundials] ...But considering the example the 66.8m meridian line of San Petronio Basilica in Bologna which was planned by the famous astronomer Govanni Domenico Cassini in 1655, the length of shadows at solstics changed. In summer +2.6cm and in winter -15.9cm. ... I can check the book for more details if you need, just let me know. Thomas I have had the enquiry below from a student and I believe the group's 'international skills' will provide more answers than I can with our lack of such dials in the British Isles. In response to my initial reply I received the second courteous message today, also below. Regards, Doug [24 Feb 09] Dear Mr. Bateman I am an architecture student at studying on astronomical architecture, Im looking for examples of domes which act as sundials, Unfortunately there isn't much detail about these kinds of domes in the world, I wonder if Your honorable could introduce me any resources related to this topic. Sincerely yours Mohammad Vaez, Bachelor of Arts Faculty of Fine Arts University of Tehran Tel. +98-21-26058691 Email: mv_20...@yahoo.com [27 Feb 09] Dear Mr. Bateman Thank you for replying to my question, The only example I have found is the Pantheon dome which the sun shines from the hole exactly at the top on the coffering surface of the dome itself which it is said to be a sundial, I will be glad to recieve any technical information from an international expert. --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial