My dials will show 9 declination-lines: 1; Equinoxes, solstices, and half-solstice declinations
2. Declinations at the ecliptic-longitudes that divide each astronomical-quarter (interval between an equinox and a solstice) into thirds. So the dials will indicate solar-declination and solar-ecliptic-longitude (expressed in thirds of an astronomical-quarter--the tropical signs of the Zodiac, labeled with their traditional astrological symbols for the signs of the Zodiac). The dials will also show Babylonian hours in the morning, and co-Italian hours in the afternoon. The Cylindrical-Equatorial shows h and dec in a clear rectangular format, and doesn't need explanation. The Horizontal Dial or course is the most easily-built stationary dial, and is particularly-easily read from any direction by someone who is near to it, and tells time whenever the Sun is above the horizon (except if it's shaded at some times of day). A Cylindrical-Equatorial Dial can be built to tell time whenever the Sun is above the horizon. The upper edge of the cylinder is trimmed horizontal, and the nodus is a bead at the middle of a string transversely across the cylinder, with the nodus-bead positioned on the cylinder's axis normal to the dial's equator-line. The nodus-bead is also level with the horizontally-trimmed top-edge of the cylinder. This Cylindricald-Equatorial is similar to the ancient Hemicycleum. ...differing from it by using a cylindrical surface instead of a spherical surface; using a string-mounted nodus-bead instead of a stick-gnomon (which I consider to be an eye-injury-hazard); and not being cut-away as the Hemicyclea usually were. 48 M November 20th 1628 UTC Michael Ossipoff On Wed, Nov 20, 2019 at 11:00 AM Michael Ossipoff <[email protected]> wrote: > Hi Franco-- > . > I like explanations that can be understood by anyone from at least > pre-secondary-school. I believe that such people can understand the sundial > and map-projection explanations that I'd use. > . > To whom would I give explanations?: Primarily to my girlfriend. She isn't > interested in math, but that doeesn't mean that those explanations wouldn't > be understandable to her if she's interested in them, interested in > lisening to them. > . > I mentioned to her that our windowsill sundial would be a > Cylindrical-Equatorial Dial, because it doesn't need any explanation, > because it shows the Sun's position in the most direct way. She replied > that she has nothing against explanation of the Horizontal-Dial, its > hour-lines and declination-lines, and considers it interesting. > . > So the first windowsill dial here will be a Cylindrical-Equatorial Dial, > followed by a Horizontal Dial. > . > In general, I believe that these subjects can be explained to anyone who > is interested in hearing the explanation. > . > So I'd offer these explanations to anyone to whom I'd suggest or offer a > sundial or map-projection. I like the idea of a sundial or displayed map > being accompanied by a pamphlet or a page that tells its > construction-formula derivation-explanation. > . > Some say that people aren't interested in explanations, but I suggest > that, rather, they're often just resigned to things being not explainable > to them. I believe that, when shown a sundial or map, they'd like it > explained. > . > It seems to me that every park, library, museum, plaza, and other > public-spaces, should have a sundial. > . > > ------------------ > > I'm not familiar with those softare products, but I'd have no objecion to > their use. I'd use drawings, but of course that software could be helpful > too, showing things in ways other than what a drawing can show. > > 48 W > November 20th > 1600 UTC > . > Michael Ossipoff >
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
