Re: The magic which is a dial!

Ahh, but sundials *do* have moving parts. That is, the entire Earth as it orbits the sun! :o) I recently got interested in sundials by thinking about techniques used to tell time when technology was young. Sundials are fascinating, and by drawing many diagrams and being obsessed with the subje

The magic which is a dial!

The current discussion on the mathematics of dialling is fascinating and very valuable, especially to a non-mathematician like me. What it does bring out is the human complexity of the simple device which is the sundial. Here is an ancient instrument which embodies astronomy and mathematics in i

Re: Fw: SCHMOYER SUNDIAL

I'll take your word for it - I'm still dizzy!! - but it sounds right... Dave On Fri, 15 Oct 1999, David R. Gagnon wrote: > Hi Dave > > The gnomon for the Schmoyer dial is asymmetric East-to-West in the > same way that the analemma is. When the gnomon is inverted, East > and West are interchang

Re: Fw: SCHMOYER SUNDIAL

Hi Dave The gnomon for the Schmoyer dial is asymmetric East-to-West in the same way that the analemma is. When the gnomon is inverted, East and West are interchanged but they are on the equatorial crescent also. Since the time scale is flipped along with the East-West flip of the gnomon, the inv

Re: conference & Compendium topics

On Wed, 13 Oct 1999, John Carmichael wrote: > I saw a lot of dialing hobbiests with paper, plastic or wooden sundials. > Maybe I'm old fashioned, but I really think that sundials should be built to > last. I think it is a pity that more of the wonderful designs that we saw > aren't being built ou

Math in sundials

Let me explain how I learned the math. More than twenty years ago I started out with Waugh's book and I could make a vertical declining dial graphically: Draw AB, draw CD perpendicular to AB etc. but I could not calculate one mathematically. Where's the log sin on the calculator? ;-) I

Martha Stewart does sundials

Dear Fred & Dialists: Please excuse the large number of e-mails coming from me this week, but we are on a thread now that is close to my heart. I'm usually more of a listener than a talker on the sundial list, but now we are on a subject that I know about, and I can finally help the group as you

Re: Math in sundials

Sundials can be constructed and appreciated by children at many ages and levels of mathematical sophistication. For example, the lines can be determined experimentally without any mathematics at all, as in the sixth grade sundial project: <http://ww

RE: conference & Compendium topics

> As for the above hour line formula, maybe the best way to teach the > beginner its solution would be to pick an example latitude and print the > pages of Natural Logrithrimic Functions from a typical trig table that have > the desired values. That way, the beginner could see how to use the tabl

Re: conference & Compendium topics

-Ursprüngliche Nachricht- Von: John Carmichael <[EMAIL PROTECTED]> An: sundial@rrz.uni-koeln.de Datum: Mittwoch, 13. Oktober 1999 19:15 Betreff: conference & Compendium topics .. > >First, I noticed that several people complained that the Compendium >contained too much higher mathe

Re: conference & Compendium topics

Dear Roger & All: Roger wrote: >Don't forget the quote from my old trig teacher, "All knowledge comes up >through a pencil." The best way to learn sundial trig is to do what you and >I have done. Work it through. Reading equations or hearing a lecture just >doesn't do it! That is why it is impor

Re: conference & Compendium topics

Hi Roger, A very nice derivation can be found in "A Choice of Sundials", by Winthrop W. Dolan, pg. 20-21. For those seeking a more intuitive approach, the graphic, inside the book's dust jacket, of a horizontal plane "embedded" within the celestial sphere gives a marvelous description of

Sundial "Societies"

Dear all, Alhough in response to comments re NASS and its journal, the Compendium, this is an attempt to speak to the dialing community at large, as embodied by this list, and by the various societies, clubs, etc.: There is a somewhat wry comment, often repeated at back-to- school time by tho

Math in sundials

Hi all, After rereading my last post, I did not wish to insult anyone by implying that C=2(pi)r was complex for them. But that formula and Tan HA = Sin L x Tan t, are complex if we wish to draw school age children into dialing. So - how do we explain that math to school children? Must we do

Re: conference & Compendium topics

Hi All, To me the question is not more or less math, but how can certain concepts best be shown or learned. Fer de Vries had a set of steps to construct that helped me understand the eot. His hemispherium is also a construction that everyone should do. The math, like C=2(pi)r, has reasons b