Karon, In contrast to my principle that sundials should indicate solar time, I still help you.
You made a sundial for solar time and shifted the hour lines 10 degrees for longitude correction. That is only correct for an equatorial sundial. For an horizontal sundial at your location (35 °N, 85° W) the correction for Daylight Saving Time is: rotation of the hour line 12 -> 11,79° 13 -> 11,61° 14 -> 12,54° 15 -> 14, 87° 16 -> 19,11° etc. Willy Leenders Hasselt in Flanders (Belgium) Visit my website about the sundials in the province of Limburg (Flanders) with a section 'worth knowing about sundials' (mostly in Dutch): http://www.wijzerweb.be Op 27-jul-2011, om 13:33 heeft karon het volgende geschreven: > That sounds like what I did. I live in Chattanooga. That is 85 degrees > longitude. So, 10 degrees off the median. So, I shifted the dial by 10 > degrees and it worked! > > I figured it out by looking at Shadows. (thanks again, BTW for that > program!!) with construction lines in I looked at the dial made normally, > then, I looked at it with the longitude correction. It took about two seconds > to see what the program had done. Then it was just finding out by how much I > needed to change it. > > So, now I have another question. Where, within a time zone in the US, is the > Solar time correct? Is it at the front of the time zone or the center? If the > entire zone is 15 degrees, I would never want to offset 10 degrees if the > prime is in the middle. But, if it is in the front, that works. > > Karon Adams > Accredited Jewelry Professional (GIA) > You can send a free Rosary to a soldier! > www.facebook.com/MilitaryRosary > www.YellowRibbonRosaries.com > > From: Donald Christensen [mailto:[email protected]] > Sent: Tuesday, July 26, 2011 10:04 PM > To: [email protected] > Subject: Re: Longitudinal shift? > > Karon > > You may be right. I'm not sure what you're asking > > I'll tell you what I do. > > I'm in Brisbane australia. Our prime meridian is 150 > > The town I live in is 147. Therefore my longitude correction is 3 degrees > > Donald > > > > > On Tue, Jul 26, 2011 at 11:43 PM, karon <[email protected]> wrote: > Do I have this correct? In order to correct for longitude, you determine the > degrees from the prime meridian of your time zone. Then, offset the 15 degree > hour angle from the center of the top circle. Your first angle is offset from > that to mark noon at equinox, then, the rest of your angles are marked at 15 > degrees from that mark in both directions, creating non marks on the equinox > all the way across. > > From there, you simply move back to marking your lines from the noon equinox > mark to the CBA point and these are your hour lines. > > Do I have this correct? > > Karon Adams > Accredited Jewelry Professional (GIA) > You can send a free Rosary to a soldier! > www.facebook.com/MilitaryRosary > www.YellowRibbonRosaries.com > > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > > > > > -- > Cheers > Donald > 0423 102 090 > > > This e-mail is privileged and confidential. If you are not the intended > recipient please delete the message and notify the sender. Un-authorized use > of this email is subject to penalty of law. > So there! > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial >
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