Andrew James cxontributed: >My idea is this: is it possible to combine the two points made? Arrange, >say, two sets each of four posts with three 0.4 mm gaps between, one set >having slightly wider posts but with the same gap, so as to make three light >rays the outer two of which diverge by the same small amount - say 0.2 >degrees - in each direction from the inner. Then balancing the appearance >of the outer rays should give a rather more accurate estimation of the angle >of the centre of the solar disc. Any takers? > What a CLEVER notion! I'll make an experimental model when time permits
Best Wishes Tony M. P.S. I can't recall if I mentioned the reason for the 0.4mm gap. For just a simple sunray a finer gap between cylindrical posts would be OK BUT my meridian layout device also serves as a two-way 'sight' and a smaller gap makes spotting even a 'dayglo' pole at a distance quite difficult.
