A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David C
Date: 2016 Dec 9, 11:54 -0800
Intuition told me that the longer the pole (not sure if it is called a gnomon) the less the effect of measurement errors. I decided that I could measure to an accuracy of 1mm. The base value is height 370mm length shadow 121mm. If I change the height by 1mm the altitude changes by 2.6'. I then calculated the error for multiples of the base value.
It seems the longer the better but........the longer the pole the bigger the error due to it not being vertical. I haven't worked that out yet. There must be an optimum pole height to minimise error.