>Shadow shortening is unavoidable. So what's your solution? < Depending on the design you might be able to fit two "false nodi" either side of where the true nodus position is. That way "Joe Public" simply judges the mid point - rather in the same way as he does when telling the time by judging the centre of the shadow cast by a cylindrical gnomon.
There is a 28 metre diameter Millennium dial in Gosport (UK) that uses a double cone in this way (it's intended to be redolent of Einstein's cone diagram) as a nodus. You can see a picture (well, sort of!) at http://www.sundials.co.uk/newdials.htm. There are several dials there, you will need to scroll down to find the dial called 'The Millennium Timespace at Gosport'. Patrick --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
