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
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