Well, there was text in the message, here it is again. ( Don't know what happened to it. )
New reflective dial? I've a window facing west, ( that is in the north-south plane ). It was easy enough with two sheets of construction paper to make a slit that was parallel to the earth's axis. Down on the floor I mounted a stick on a tripod so that it was at a right angle to the strip of light. On the stick I mounted ( with modeling clay ) 3 little 1 inch mirrors. I adjusted each one so that on each hour each spot was on the beginning of a different square ceiling tile. There was enough room in between on the stick to set mirrors at the half hours to reflect to the middle of the ceiling tiles. So, I had a sort of linear reflective sun clock. It looks like I could take a 1 inch wide piece of reflective mylar and warp it so that the clock would be continous, but I ( so far ) can't visualize how it would have to be shaped. I imagine that in the declination plane the mirror(s) would have to be concave in order to restrict the movement to a narrow strip across the ceiling with the changing of the seasons. I can make the hour lines on the ceiling go in either direction. In one case the array of mirrors is more or less concave, in the other, convex. All the years of crashing computers, faulty backups and declining retirement income have left me without any familiar mathematical software that I'm capable of using to analyse these arrays. I would imagine that the reflective surface(s) would bear some relation the the cycloidal polar dial, but that is intuitive. Have any of you fine mathematical folk looked at this situation? ( I'd like to be able to sleep nights again, rather than try visualizing this dial. ) Edley McKnight --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
