Bill Gottesman wrote: > >One of the great things about this list is the opportunity it affords to >admit when you (me) are mistaken. I have played around with a shadow >sharpener, and can now see that it really does project a small, fairly >sharp, >central shadow narrower than the 2 minute width of the solar disk. I think >it would make an ideal device for use with an annalematic noon mark. I have >attached a .gif of how I think the sharpener works, if anyone is interested. > I think it was my query which gave rise to your gently-dismissive 'this is the Holy Grail of Sundialling' comment but that is adequately recompensed by your excellent GIF explaining how the thing probably works.
Brilliant! Tony Moss
