Roger Bailey contributed: SNIP > >Tony, your sketch is worth 10,000 words. I see from the sketch how things >are laid out and points projected to different planes. But I am having some >trouble with the words as you seem to be starting at the solution (P1) and >working back to find the location of the sun. I would thing you need to >start with the time and time angle and work towards the point on the >cylinder from there.
SNIP To avoid making the diagram too complex I left out the way in which the perpendicular view of the inclined trigon is achieved from a true circular view. Your re-draw supplies what I left out Roger. For those who are similarly puzzled I've re-worked the original diagram leaving out some of the previous detail but showing how it is done in drawing board methodology although I must admit that I cheated and simply 'squashed' a pre-drawn trigon electronically in Adobe illustrator sent herwith to my JPEG sub-list as a GIF. (on request to others as it won't pass Daniel's file size filter)
