Hi Mac, I have only hearsay evidence, but I'm told, since it has a latitude setting ring, a declination setting ring and an hour angle ring, when the eyepiece and prism are removed and the main mirror focused on the sun, as observed on a surface placed at it's focal point the declination and hour angle can be read off, looked up in a table, and the sun time read off.
BTW, I've been looking at some your designs for Italic hours, very nice, very appreciated! I consider you an early charter member of the "Friends of Reversed Italian Hours" club. ( Well, if there really is such a thing. ) There are a number of such early charter members on this list. Searching the Archive shows a lot of you. Hmm. That is also about when I was walking around a barrel, grinding a mirror. There are patents filed by Porter that are similar, but using a refractor telescope as found on Google Patent with the search "Porter Telescope" Best Wishes! Edley McKnight. > Hello Friends, > > The Summer 2007 issue of Vermont Life magazine contains a nice > article on Stellafane, a convention of amateur telescope makers which > convenes each summer in Vermont, USA. > > Prominent among its founders was Russell W. Porter, architect, > artist, mechanical genius, Arctic explorer, telescope maker, and > dialist. > > A sidebar features Porter's Garden Telescope, described as an elegant > combination of a sundial and a reflecting telescope. A replica is > being produced by Fred and Russ Schleipman of Norwich, Vermont. Point > your browser at: > > http://www.gardentelescopes.com/ > > (be sure to read the "History" and "About Us" pages) > > > Porter designed and produced several different cast bronze sundials. > Some may be owned by members of this List. > > My question is, how, exactly, does the elegant device pictured in the > magazine (and on the website) function as a sundial? > > Best wishes, > > Mac Oglesby > > (Who, 60+ years ago, was walking round and round the barrel, trying to > make a reflecting telescope mirror.) > > > > > > > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
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