Hi John, That's great to build a sundial on your ceiling. It isn't difficult to create the pattern with all kind of lines you want on your ceiling dial. Just use the program Zw2000, option "mirror sundial". The mirror may have any inclination and/or declination you want and with some trial and error you will find the best solution for your room. The mirror is placed on the endpoint of the (imaginary) gnomon, of which the length should be known, pendicular to the ceiling. The ceiling itself also may have any declination and/or inclination, but usual this will be inclination 180, declination 0 degrees. Show us the result.
Best wishes and a happy New Year. Fer. Fer J. de Vries [EMAIL PROTECTED] http://www.iae.nl/users/ferdv/ Eindhoven, Netherlands lat. 51:30 N long. 5:30 E ----- Original Message ----- From: "John Carmichael" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Saturday, December 29, 2001 3:30 PM Subject: Re: Ceiling Sundial > The past year, I've been playing around with a little 1cm. square mirror to > be used for ceiling sundials that Fred S. gave us at the Hartford NASS > conference. > > I have a large room with a big ceiling. The roof of the house has an > overhang over the southern window, however. In order that the level mirror > not be shaded by the overhanging roof in the summer, I found that I had to > lower the mirror closer to the floor. This of course caused the hour > "spots" to be shifted far to the north on the ceiling. > > I wanted the ceiling dial face to be somewhat centered on the ceiling, but > lowering the mirror shifted the hour lines too far north on the ceiling. I > found that I could correct this by tilting it slightly to the south. Tilting > the mirror will also help to center the dial face on a ceiling of a room > that declines from south. > > Now, tilting the mirror makes calculating the hour lines mathematically very > difficult (for me). But using the "connect the dots" method that we've been > discussing greatly simplifies the drawing of the dial face. It just takes a > long time (six months). > > > John > > John L. Carmichael Jr. > Sundial Sculptures > 925 E. Foothills Dr. > Tucson Arizona 85718 > USA > > Tel: 520-696-1709 > Email: [EMAIL PROTECTED] > Website: <http://www.sundialsculptures.com> > >
