Hello Duane, This is a good question, one that has challenged us since the railways forced the introduction of standard time. My initial advice is to "Get over it!". Sundials show solar time, in tune with the rotations and orbits of our universe. Clock time is defined by law and international conventions. This is fine for catching an airplane but it is a totally arbitrary system of time. There are translations available but the bottom line is the clocks are wrong. Go with the sun.
I have mellowed a bit and now accept that there are good reasons to show clock time on a sundial. The advice that you have been getting for slewing for longitude and adding an EOT correction is appropriate. This used to be what we were stuck with to show mean clock time. But things have changed with the wonderful subtle design by Hendrik Hollander, a mean time sundial with conical gnomon. This dial looks quite normal, with straight lines and smooth curves but it incorporates the equation of time and shows clock time. Hendrik won the prestigious "Sawyer Dialing Prize" last year for this concept and has published the details in in the NASS Compendium, Sept 2006. The latest Compendium digital edition, June 2007, included software by Brian Albinson to design such a Hollander mean time dial for your location. Google "Hendrik Hollander sundial" for more leads. My final recommendation is to not construct a sundial based on Hollander's concepts until you can explain the hidden subtly to your friends and family. Actually this is not a recommendation but a challenge. I am not there yet. Welcome to the Sundial Mailing List, Roger Bailey Walking Shadow Designs www.walkingshadow.info NASS Secretary www.sundials.org ----- Original Message ----- From: [EMAIL PROTECTED] To: sundial@uni-koeln.de Sent: Friday, June 01, 2007 1:57 PM Subject: Equation of Time Greetings, I am a new member and have what is probably a very simplistic question. My apologies in advance. When considering a flat, fixed sundial (not an equatorial dial) it appears that to get the sundial as close as possible to watch time you set it to the latitude and then adjust it for the longitude when laying out the hour lines. Having done all that, am I right in assuming that you are still at the mercy of the Equation of Time and will need to add/subtract minutes to the dials time to equal watch time? - or is it somehow possible to adjust a flat, fixed sundial to incorporate the equation of time also? Thank you for any guidance/help you will tender. Sincerely, Duane Thomson ------------------------------------------------------------------------------ See what's free at AOL.com. ------------------------------------------------------------------------------ --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.472 / Virus Database: 269.8.6/828 - Release Date: 01/06/2007 11:22 AM
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