Re: Twisted band sundial

[Fritz Stumpges]

Hi, This is an interesting, simple and esthetically pleasing dial.  I may be off but follow this.  Take off your belt and give it a half twist. With one eye become the sun and look down at this polar aligned belt, straight above it as if at an equinox.  Now turn it until you have the thinnest section (belt thickness) in the middle.  You can see that half of each side is illuminated by your eye.  The light/dark shadow lies at the junction and is not visible by the sun. This I believe is noon on an equinox as is the photo I was able to open on Luke's egeskov link.  You can rotate to the right (east)  90 deg and see sunrise.  Either side (both) could be inscribed.  A full 360 deg twist was used even though primarily only the  center 180 deg is used.  One possible drawback I can envision is that the seasonal change in the sun's incidence angle will give quite a large error reading as this dial appears sensitive to this angle also.  You can see this in your belt by tilting it and watching the narrow shadow line move without changing hour angle.  The shadow is also angled across the belt instead of perpendicular as in the photo and at equinoxes.  I have to run now and hope this is not all a quick illusion of mine.  I sure love all of these sundial ideas and it is ever fun imagining them.   Your new sundial list friend Fritz