Mike Shaw wrote: >Jon Noring wrote re standard time heliochronometers: >>I'm especially intrigued to know of designs that do not require any >>alignment interaction nor adding or subtracting minutes to >>compensate for the EoT
>I have several so called heliochronometers, in particular I have a >Pilkington Gibbs and a Schmoyer -- though both are, sadly or gladly, >according to your point of view, "interactive". I recall visiting your web site at the start of my quest, but a second visit is more rewarding now that I have a better grasp of this topic. The Schmoyer is very interesting since it uses a 3-D curved slot to compensate for the EoT. Fascinating. >I do have one "non-interactive" one - an equinoctial made by Silas >Higgon. It uses two interchangeable specially shaped gnomons, one >for use when the sun is travelling south, and the other for when it >is heading back in my direction. Adjustment is required on four days >a year - at each solstice, and when the clocks change. It's not too >onerous. There are two photos of it - the first two pictures in the >"Picture Gallery" section of my web page, with a link to >Silas' web page. Thanks. I recall seeing quite a few equatorial sundial types which use swappable analemma-shaped gnomons for both sun directions. Most of them were in Germany (those precision-driven Germans. :^) ) Both the Schmoyer and Higgon heliochronometers suggest the interesting possibility of using a precision-curved mirror or prism to redirect the solar beam which will compensate for the EoT. Of course, one would need two of them to cover the whole year. Has anyone built a sundial using an EoT-corrected mirror/prism/lens? Thanks again for mentioning your interesting collection of heliochronometers. Jon Noring -
