Re: On northern vs. southern dials

[Anselmo P�rez Serrada]

Gianni,       Thanks a lot for the graph. As for the general case, if you use Fer de Vries'  routines you can do the same with not much additional effort.   Anselmo Perez Serrada ----- Original Message ----- From: Gianni Ferrari To: sundial@rrz.uni-koeln.de Sent: Monday, March 04, 2002 7:13 PM Subject: Re: On northern vs. southern dials Anselmo et All, also I  have obtained  to the same conclusions of Fer ( and others)  ( Latitude = 45d) For curiosity I attach the graph of the daily mean number of hours of illumination of the vertical plane at different Latitudes. The plane is illuminated for a period (mean) of 9h 54m,   that is for 3615 hours in the whole year.  There are 4 days in which the plane is illuminated for this period of time :  - when the Sun's Decl. = +15.16d :  May 5 and August 11 (the Sun hiddens behind the vertical plane)  - when the Sun's Decl. = - 15.16d :  February 7 and November 3 (the Sun sets in front of the plane)  More complex is the problem if the plane is declining and not  Southward  Best wishes Gianni Ferrari