You likely have a sheet of glass already clamped in place nearby -- the window. Couldn't you calculate a vertical dial for the right orientation, print it on a transparency, tape the transparancy to the window glass, and mark out the lines with a laser pointer or perhaps with a projector that casts shadows of the lines onto the ceiling?
--Art -----Ursprungliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Auftrag von Dave Bell Gesendet: Wednesday, January 02, 2002 8:28 PM An: J Lynes Cc: Mailing List Sundial Betreff: Re: Ceiling Sundial I like it!! Printing the dial artwork on transparency film should work well. Rub it down onto a thin sheet of glass supported in a frame, perhaps with a film of water or the like to keep it in place. The frame would need to be accurately leveled and oriented, but could easily be clamped in position, once that is determined. One hitch might come in, if the mirror is placed on the inside sill of a fixed picture window, making it hard to get the dial center over the mirror... Dave 37.29N 121.97W On Wed, 2 Jan 2002, J Lynes wrote: > Here's a simpler proposal. > Transfer the declination lines and hour lines of a horizontal sundial onto a transparent sheet. > Mark a small circle on the centre of the mirror. > Support the horizontal transparent sheet, rotated from north to south, with its nodus vertically above the centre of the circle, at a distance equal to the height of the transparent sundial's gnomon. > Project a laser beam through the transparent sheet onto the centre of the circle. Make sure the beam passes through the sundial scale at a point corresponding to some chosen time and date. > The reflected spot on the ceiling is the appropriate point on the ceiling sundial. > Repeat for other dates and times. > John Lynes >
