Chuck O'Connell wrote: > > Hello All, > > Does anybody know of a 'fairly complete' list of things > people put on their sundials? (sundial furniture) > > By this I mean hour lines, date lines, unusual uses, etc. > > There is a solar refraction phenomenon called > 'circum zenithal arcs' which occur only when the sun is > between 18 and 26 (or is it 16-28) degrees in the sky. > It appears as a blue shifted rainbow that appears directly > overhead as a circle centered at the zenith! > > I'm including lines on my sundial to show when the sun is > between these altitudes. > > It got me wondering what else people have put on theirs. > > Chuck
Hello Chuck, Here is a list (as far as I know) of possible things to put on sundials. If anybody knows of other lines I would be pleased to hear about it. local time local time with half analemma period 21/12 - 21/6 local time with half analemma period 21/6 - 21/12 standard time standard time with half analemma period 21/12 - 21/6 standard time with half analemma period 21/6 - 21/12 siderial time period 21/12 - 21/6 siderial time period 21/6 - 21/12 date lines (month,day ) declination lines altitude lines azimuth lines babylonian hour lines italian hour lines antique hour lines islamic prayer lines planetory hour period 21/12 - 21/6 planetory hour period 21/6 - 21/12 ascendants period 21/12 - 21/6 ascendants period 21/6 - 21/12 decendants period 21/12 - 21/6 decendants period 21/6 - 21/12 astrological houses French revolution time In these kinds you even can variate. For example the Qibla on a sundial: this is a certain line of azimut. Declination lines: for a birthday of your wife, son, daughter, friend or of a saint and so on. French revolution time: Can be calculated as normal suntime lines. Except for planatory hours I have seen them all on some dials. Remember: I use for planatory time the definition as given by Joseph Drecker (1923), not the antique time. Sometimes you will find phenomenae of the sun for place A on a sundial placed at B. In fact you may vary as much you like and as you did for altitude lines. Fer de Vries.
