Hello all,
the capuchin hour limit is a part of an "equilatere" hyperbola. Its center
is K on Figure 3 of the Fer de Vries's article. By using a xy system of axis
with origine at K, the equations of the "assymptotes" are, at the latitude L:
y = - x.tan L/2
y = x.tan (90 - L/2)
and the equation of the hyperbola:
x.x - y.y + 2.x.y.cos L/sin L + BK.BK = 0
Of course, the point B is on the hyperbola and it's also the highest point.
I came across this problem when I worked on the equations of the central
projection analemmatic sundial with circular curve.
Best regards
Yvon
Yvon MASSE 7, rue des Tilleuls 95300 PONTOISE FRANCE
E-mail: [EMAIL PROTECTED]
