Hi Judith and John, I downloaded your spreadsheet today and gave it a test run. I found it to be user friendly and appropriate for general use through the internet. The operating instructions up front give the novice a good introduction. I can see it being quite popular for school projects. It doesn't plot the results but appropriate drawings are available on John's website. All that is missing is a link to the longitude correction. While the gnomonics (astronomy, trigonometry and geometry) are not explained, the formulae used for generating the numbers are provided. I view this as an excellent resource. Thanks for posting it.
I developed a similar analemmatic design spreadsheet and made it available to NASS members and those on the sundial mailing list. I did not offer it over the internet for anyone to download. This was deliberate. It is not a user friendly program but a hard core technical calculation spreadsheet. You need to be used to Excel and gnonomics to use it. It contained errors and bugs. The error trapping of trig ambiguities was manual. It does has some extra features including charts of the results and the calculation of declination lines for specific dates/declinations. The latest version also includes the sunrise seasonal marker proposed by Mike Deamicis-Roberts. My spreadsheet does not have any operating instructions or background explanations. To explain the math and science, I also offered my NASS presentation, "How Long is my Shadow? The Use of Declination Lines in the Design of Analemmatic Sundials". Both spreadsheets have their use. Yours is better suited for open distribution, mine (I think) for experienced users. I bet that more dials will be built from yours than mine! I am at four now: Calgary Science Centre Amazement Park, Elliston Park Calgary, the CD sundial dial on my deck and Mike's Seasonal Dial (under construction). There may be others that I don't know about as the spreadsheet was distributed from Baffin Island to Australia. Also, thanks John for the cylindrical dial posting. I have been interested in making one of these for quite a while. Cheers, Roger Bailey Walking Shadow Designs N 51 W 115 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Romano, Judith Sent: January 8, 2002 5:22 AM To: '[email protected]' Cc: John Hoy (E-mail) Subject: Garden/Human Sundial > There is a new fill-in form designed to provide a "free" resource in which > to obtain a simple understanding of the mathematics behind how a > GARDEN/HUMAN SUNDIAL works, while computing the calculations > automatically. > > The EXCEL spreadsheet was designed for Northern Latitudes and Western > Longitudes. It not only includes longitude correction, but also converts > the information to the more common measurement of feet and inches. This > easy and affordable outdoor project is perfect for getting children > involved in both math and science! > > The "link" is available at John Hoy's website (You Can Make a Sundial!) in > the "Full Size Analemmatic Dials" section -- > http://www.grex.org/~jh/dial/index.html#ana. Please feel free to post > this "link". Let me know if you have any questions. > > Judith Romano > >
