Dear Andrew, You are quite right...
> I thought that you were looking for a > "straight-edge" and compass construction > on the sheet of paper. Yes. I was! Don Snyder gave us pointers to what I was hoping for... > first find the ellipse center > > http://www.had2know.com/makeit/find-ellipse-center.html > > then the ellipse axes > > http://www.had2know.com/makeit/find-ellipse-axis-focus.html Unfortunately, I got side-tracked by the "folding-paper" method. That is a practical method but not what I really wanted! > One way to draw the ellipse in the > first place is to adopt the "Trammel > Method". Yes. That is probably almost as well known as the String and Pins method. It also gives good results if you are careful. > If you start by drawing the major & > minor axes on a sheet of paper and > plotting the ellipse from there, you > have no need to search for the axes > because they are already drawn on > the paper template! Quite so, but my real-life problem is that I take delivery of an elliptical piece of slate WITHOUT the axes marked on so I have to find them! > Am I missing something? No. You stayed with the question and didn't get side-tracked like the rest of us :-) Frank --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
