Dear Roger,
Thank you for posting the directions for finding azimuth. I have
found the "Dialist's Companion" equally valuable for some of the same
purposes as you describe.
Your explanation brings to mind how it would be possible to make an
azimuthal dial for a window seal. The use of Zevonplot from Fer de
Vries makes it very easy.
Sincerely,
Warren Thom
Roger Bailey wrote:
> Hello Fellow Dialists,
>
>
> The solution was simple. Measure the azimuth of the sun through the
> window!
> The windows in well built modern houses (an oxymoron) are vertically
> set in
> the plane of the wall. The shadow of the window frame on a pad of
> paper
> held horizontally, with one edge pressed on the glass determines the
> azimuth of the sun with respect to the plane of the window at that
> instant.
> All you need to do is mark the shadow line on the paper and the exact
> time.
> Take several readings, hours apart, for better accuracy and a check on
>
> measurements. To keep the orientation correct, I also note the rough
> heading of north and add to the shadow line an arrow pointing to the
> sun.
>
> Data reduction is still a problem. You have to correct for clock
> error,
> know the latitude, longitude, equation of time and declination of the
> sun
> and solve the usual spherical trigonometry equations to determine the
> azimuth of the sun. This is greatly simplified using "The Dialist's
> Companion" a program written by Terwilliger and Sawyer and published
> by
> NASS. Enter the appropriate data; the program solves for azimuth. From
> that
> calculated azimuth compared to the measured azimuth, the declination
> of the
> window (wall) is determined by simple geometry.
>
> The technique works very well. I have used it many times with
> excellent
> results. Generally the declination results agree to within half a
> degree.
> Errors are obvious as outliers.
>
> Cheers,
>
> Roger Bailey
> Walking Shadow Designs
> Canmore, Alberta, Canada
>
