@rrz.uni-koeln.de
Date : lundi 24 mai 1999 03:21
Objet : plotting timelines for giant sundials
Hello dialists:
I have been giving more thought to the practical aspects of designing and
constructing a very large sundial, particularly the problem of accurately
laying out the time lines.
THE PROBLEM
John,
I currently have a similar problem of helping to delineate a large dial,
this time a vertical decliner with a 17 foot gnomon which is to be carved
directly into the wall of a tower. Needless to say, the wall is not
absolutely flat.
My current solution has been to build a laser trigon
Hi John,
Here is a try:
John Carmichael wrote:
Snip
THE PROBLEM: The plotting techniques which use tabulated angles or
computation produce timeline plotting angles in degrees which the dialist
must mark onto the dial plate using a protractor. These angles will be as
precise as the
John,
SOLUTION C: What if I built the gnomon first and use its shadow to tell me
the position of the time lines With this method, no calculations,
plotting, protractors or tape measures are needed. Using a shadow
sharpener, the exact position of each timeline could be marked onto the dial
Hello dialists:
I have been giving more thought to the practical aspects of designing and
constructing a very large sundial, particularly the problem of accurately
laying out the time lines.
THE PROBLEM: The plotting techniques which
John,
There is another solution, one well-known to machinists.
Recalculate ALL your lines, positions etc. as x-y coordinates and
then set out the dial in whatever size you want from some convenient
origin. The only question is the resolution of points used to draw
curved lines. If too
