Hi Mac:>
>In my Mayall copy the analemma constructions (graphical on pages 197-199;
>by formulas on pages 201-202) are not for vertical nor horizontal plates,
>but for a plate parallel to the earth's axis.
Yes, I guess the proper terminology for Mayall's analemma projection that he
uses in his equatorial heliochronometer would be called a "polar analemmatic
noon mark", according to the article by Allan Mills in the BSS Bulletin,
June '99.
>
>Waugh gives formulas for computing a horizontal analemma on pages 24-28. I
>recommend Zonwvlak or a similar computer program.
Eureka! The formula! I remembered the endearing little story Waugh told
about laying out tacks on his floor every day for a year to get his
analemma, rather than doing the tedious computations, but I didn't remember
that he gave a formula. I'm sure you are right about ZONWVLAK as everybody
speaks very highly of it. I have the digital version that came with the
Dec. 97 Compendium and have enlisted the help of somebody better at
computers than I am. I consider mastering this program a top priority in my
sundial education! I hope that we can wade our way through it without too
many problems as I don't want to bother you all more than necessary.
Thanks again for all your help, Mac,
John
>
