Darek, You need only one hour-angle in the morning and one hour-angle in the afternoon to calculate the latitude and the orientation of the sundial. The hour angle = 15° x (12 - hour)
On my website you can see the calculation method and a calcualtion-example for a sundial in the abbey of Rolduc (The Netherlands) The language is Dutch but the formulas are international. http://www.wijzerweb.be/berekening.html Some translations: H =hour angle in the morning H' = angle of the corresponding hour line angle with the 12 o'cloCk hour line J = hour angle in the afternoon J' = angle of the corresponding hour line angle with the 12 o'cloCk hour line phi = latitude D = orientation of the sundial (gnomùonic declination) Willy Leenders Hasselt in Flanders (Belgium) Visit my website about the sundials in the province of Limburg (Flanders) with a section 'worth knowing about sundials' (mostly in Dutch): http://www.wijzerweb.be Op 11-jan-2012, om 00:32 heeft Darek Oczki het volgende geschreven: > Dear Diallists > > I've got two practical questions: > > 1. Let's say I have a photograph of a sundial. I do not know where it was > originally located. Is there a way to discover the values of the declination > and latitude it was designed for? There are clear hour and declination lines > on the dial. > > 2. A friend of mine is helping a student in an attampt to reconstruct an old > missing dial. They need a software which allows to make an animation of a > shadow's path over the dial. Is there anything that would help them? > > I would be most grateful for any suggestions. > > -- > Best regards > Darek Oczki > 52N 21E > Warsaw, Poland > > GNOMONIKA.pl > Sundials in Poland > http://gnomonika.pl > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
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