On 12/10/2014 02:49 PM, Levi Pearson wrote: > If you haven't seen this site yet, it might be helpful: > http://wvaughan.org/sundials.html
I've seen all kinds of web sites on sundials but not that one. Fascinating stuff. Thank you. > It includes parametric equations for the conic sections of a > gnomonic-projection sundial, and an interesting derivation of how they > work based on an idealized spherical sundial. I found it very > enlightening to view the model of a sundial as a spherical model with > a point shadow-caster along with a projection of the spherical model > onto a plane. Yes that is very interesting. I'll have to digest the information in there. It could be what I'm looking for. Been reading up on hyperbolas and conics for some days. I think I'm closer. Essentially I'm writing code to generate a subset of the sundial types that the web site you mention talks about. And it can make the chart on a flat surface tipped to any reasonable inclination. So the wall of a building for example (facing south, east or west and in between). Or flat on the ground, or inclined. When I figure out this little issue, I can post some code. I got into this when I was traveling and I saw a really neat sundial that used a cylindrical face that could read both time and date, and decided I wanted to know how to build it (turns out that kind is super easy, since the date lines are parallel, the hour lines are even 15 degrees apart, and it can easily work in any latitude and longitude). Plus the history of sundials is super fascinating and I'd never known about it before. /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
