25 Apr 98 Hello Rodger,
You wrote: (snip) >The problem in such a design is to accurately measure the declination of >the wall. Compass measurements are inaccurate. Plumb bob or nail shadow >measurements work but are awkward to do correctly. The math to solve for >solar azimuth is also intimidating. I faced this problem recently when I >designed a dial as a gift for my sister-in-law who lives on the other side >of the country (and Canada is a large country). On a short visit I had to >get the appropriate measurements without anyone suspecting what I was >doing. The usual tools like step ladders supporting plumb bobs, carpenters' >squares etc were unavailable. > >The solution was simple. Measure the azimuth of the sun through the window! (snip) Thanks for sharing this neat way of determining the declination of a wall. Your process has a lot to recommend it over the method I normally use, which involves a plumb bob and carpenter's square. I particularly like the idea that your method may be exercised covertly. Also, indoors out of the [cold] wind sounds just fine! All the best, Mac Oglesby P.S. >My sister-in-law was surprised by the gift and amazed by the accuracy of a >dial designed and built thousands of miles from it's unique location. If >you are interested, e-mail me and I will send pictures (106 kb JPG) and >operating instructions for the dial. I've seen photos of two of Roger's beautiful dials and strongly recommend that others request his pictures.
