Hi all,
becouse of some request I received about my (it is not mine, I
found it in a last century book) method to find the orientation of a
wall, and becouse I have not time enough to traslate my notes in english
immediately, I describe here hardware. Software consists in a procedure
for "Matcad" that is avaiable (as it is) even immadiately.
Hardware consists in a little L-shaped board with a plumb string that I
suspend on the wall. On a sheet of paper that is on the orizontal part
of the board, I collect the shadow of the string at least 5 times every
10-20 minutes. It is very easy, using a good protractor, to measure the
angle between the ortagonal line to the corner and each shadow line.
Knowing also the time (civil time) of each shadow line, Sun's
declination and latitude and longitude it is possible to deduce the
orientation of the wall with the accuracy of 1/4 degree that is enough
evene for large sundials.
Becouse I have not anonimous ftp , if someone wants my matcad procedure
I can send it in attachment.
Some days ago I promised the new edition of my notes about the
astrolabe. Now the booklet (in italian) is ready. The booklet has text
and figures. You can see only the text at this address:
http://www.arcetri.astro.it/science/Reports/98/5_98.html
English version in the future. If you decide that italian version is
right for you I can send you a copy by ordinary mail. Ask me (again)
sending your address.
Best regards and my apologies for the terrible english I use.
Piero Ranfagni
