Hi Frank--
Thanks for the thorough and complete explanation about conic-sections for
declination-lines for flat-dials.
Yes, but I want to be able to explain the actual numerical calculation of
the declination-lines to someone. ...to explain the derivation of the
actual formulas for the
Dear Michael,
You ask:
> Is there an easy explanation/derivation for the solar-declination lines
on a Horizontal-Dial?
Yes. Here is the thought process:
1. You start with a plane and a point (the point must not be in the plane)
2. Call the plane the 'dial plate' and call the point the
