2 questions: declination animation
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
RE: 2 questions: declination animation
Hi Darek, IF you have a straight-on photograph, you can measure the angles between the hour lines and the 12 o'clock line. You can then reverse engineer the dial to figure out the latitude and declination. You will probably find some scatter of values, but this is normal. If the gnomon is present, you can measure that too. Sara -Original Message- From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Darek Oczki Sent: Tuesday, January 10, 2012 6:32 PM To: sundial@uni-koeln.de Subject: 2 questions: declination animation 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 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: 2 questions: declination animation
Hi Darek and all There is a feature in my program Shadows Pro to reverse engineer a vertical sundial from its picture. It does not correct aberrations due to the camera objective but if the picture is taken exactly in front, it works pretty well. You can see a screen copy on this page: www.shadowspro.com/en/gallery12.html Regards François www.shadowspro.com -Message d'origine- De : sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] De la part de Darek Oczki Envoyé : mercredi 11 janvier 2012 00:32 À : sundial@uni-koeln.de Objet : 2 questions: declination animation 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 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
