Hi Dave, I am glad that you have enjoyed experimenting with the spreadsheet. I was also surprised by what you found. I had not noticed the effect until I visited Frans Maes website www.biol.rug.nl/maes/sundials/ and saw that the declination curves can overlap. It depends on the size of the dial, the height of the gnomon and the latitude. This is why I wrote the original spreadsheet, to investigate these design parameters and their effect on the declination lines, the path of the shadow.
I missed feature that Helmut has added, the proper handling of east longitudes. You and I may not care but this is an essential feature for European users. Roger Bailey Walking Shadow Designs N 51 W 115 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Dave Bell Sent: April 15, 2002 10:38 AM To: [email protected] Subject: Re: Spreadsheet for analemmatic sundials This is great! Thank you for sharing it, Helmut. After downloading it, I couldn't help playing with it for a while... I noticed something I hadn't before; maybe someone more knowledgable about analemmatic dials could explain it for me: I generated a series of dials, with the sun-path set for the major quarter points of the year, starting with the Summer Solstice. I noticed that three of the four paths all crossed the minor axis at the same point, but the Winter path was (more like I expected) 'way north of the ellipse. I ran more, filling in the missing months, and found that apparently all dates from the Vernal Equinox through Summer to the Autumnal Equinox, passed through that same point, while all dates in the remainder of the year were progressively farther North, with a maximum at Winter Solstice. Why don't the summer-ish paths fall to the South of the singular point? Dave 37.29N 121.97W On Mon, 15 Apr 2002, Sonderegger Helmut wrote: > Hi to Everybody, > > some time ago Roger Bailey designed an Excel-spreadsheet for analemmatic > sundials. I think, it was a presentation for the NASS-meeting at Hartford. > I made some changes and added some features. For those who are interested, > please download the extended version ANALEMM.zip from my homepage > http://webland.lion.cc/vorarlberg/280000/sonne.htm > (offered with permission by Roger). > > Hints at errors or any suggestions would be appreciated! > > Helmut Sonderegger > > - > - -
