dear Frank, I use the trigonometric sphere.I get the formula for the angle (alpha) between the max slope line and the n italian line, then the distance (s) of the italian line from the base of the orthostyle O.
The formula is for any oriented dial.
I attach:- the trigonometric sphere: P is the observer, N the North, P0 the horizontal equivalent dial, I1, I2, In are the italic planes - a picture with the lines on the dial: s is the distance between the italic hour line and the base of the orthostyle
- the formula, where:phi 0 and lambda 0 are the coordinates of the horizontal equivalent dial; they are calculated with i, the zenithal inclination, d, the declination and phi, the latitude. Jn is the dihedral angle between the n italic plane and the dial; it is useful to calculate s omega n is the angle between the n italic hour line and the substyle; with sigma, the substyle angle, you get alpha, the angle between the max slope line and the n italic hour line.
s is calculated with Jn and a, the height of the orthostyle. ciao Fabio Fabio Savian fabio.sav...@nonvedolora.it Paderno Dugnano, Milan, Italy 45° 34' 10'' N 9° 10' 9'' EGMT +1 (DST +2)
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