The public stationary sundial in my town is mounted normally for Local True Solar Time. It’s correction-plaque gives un-adjusted EqT, with an instruction to add a certain number of minutes for the longitude-correction.
On Sun, Apr 2, 2023 at 17:26 Steve Lelievre <steve.lelievre.can...@gmail.com> wrote: > You don’t need two wedges, you just skew the positioning to do both > adjustments in one. > > If you have The Compendium vol 7 issue 1, take a look at the articles by > Fred Sawyer and Bill Gottesman. > > Steve > > On Sun, Apr 2, 2023 at 17:20, Rod Wall <rodwall1...@gmail.com> wrote: > >> Hi Jack and Steve, >> >> To implement what Jack has indicated. You could have two wedges one on >> top of each other. One for Latitude correction and one for Longitude >> correction. >> >> You could also just use a Longitude correction wedge if you only wanted >> to correct for Longitude. >> >> When writing instructions. Please also include people who live in the >> southern hemisphere, we do also have sundials. >> >> Do I have this correct? >> >> Roderick. >> >> On 3/04/2023 9:24 am, Steve Lelievre wrote: >> >> Jack, >> >> Try out my calculator! You can specify a time zone meridian for the dial >> at its original location, or at its new location, or both. If there is an >> effective longitude change, it'll tell you how to position (twist) the dial >> on the wedge and how to orient the wedge itself, turning it away (rotating >> it ) from the meridian line. >> >> Steve >> >> >> On 2023-04-02 3:59 p.m., Jack Aubert wrote: >> >> I thought about this briefly. I had always thought that the purpose of >> the shim or wedge adjustment was to tip the dial north or south so that >> dial is at the latitude it was originally designed for. If the original >> dial has a built-in longitude correction, that could also be factored into >> a wedge which would have both a north-south and east-west axis. But a >> wedge would not work if it moved the gnomon out of alignment with the with >> the rotation of the earth (or the celestial sphere). I think a >> longitudinal adjustment would only work if he original dial had a time-zone >> offset included by rotating the hour lines with respect to the origin of >> the gnomon. >> >> >> >> Does this make sense? It sounds like a good project for a 3-D printer. >> >> >> >> Jack >> >> >> >> *From:* sundial <sundial-boun...@uni-koeln.de> >> <sundial-boun...@uni-koeln.de> *On Behalf Of *Steve Lelievre >> *Sent:* Sunday, April 2, 2023 5:16 PM >> *To:* Michael Ossipoff <email9648...@gmail.com> <email9648...@gmail.com> >> *Cc:* Sundial List <sundial@uni-koeln.de> <sundial@uni-koeln.de> >> *Subject:* Re: Adjusting dial to new location >> >> >> >> Michael, >> >> Yes, I recognize that to get Mean Time involves Equation of Time >> adjustment and that Equation of Longitude can be handled there to give >> Standard Time (or DST). >> >> But anyway, my inquiry was to seek an online wedge calculator. Nobody >> identified one and a week seemed an adequate wait for responses, so I've >> just written one. Anyone who's interested, please see >> >> >> https://sundials.org/index.php/teachers-corner/sundial-construction/367-easy-dial-adjustment-for-your-latitude >> >> Cheers, >> >> Steve >> >> >> >> On 2023-04-02 1:41 p.m., Michael Ossipoff wrote: >> >> I just want to mention that the shim under the north or south edge of the >> dial is only for latitude. Longitude is corrected-for by changing the >> constant term of the Sundial-Time to Clock-Time conversion. >> >> >> >> But usually Sundial-Time, Local True Solar Time, is what I’d want from a >> sundial. >> >> >> >> On Sun, Mar 26, 2023 at 14:30 Steve Lelievre < >> steve.lelievre.can...@gmail.com> wrote: >> >> Hi, >> >> Can anyone point me to an existing online calculator for making a wedge >> to adjust a horizontal dial to a new latitude and longitude? >> >> I am not asking for an explanation of how to do the calculation; I just >> want to be able to point people to a calculator that has already been >> proved on the internet. It should use the original location (latitude >> and longitude) and the new location to calculate the angle of slope of >> the wedge and the required rotation from the meridian. >> >> Many thanks, >> >> Steve >> >> >> --------------------------------------------------- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> >> ---------------------------------------------------https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> -- > Cell +1 778 837 5771 > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > >
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