For complete generality: If your sundial was made for a latitude greater then yours by an amount called “DeltaLat” (which could be positive or negative), & if you want the dial to give LTST for a longitude 7 degrees west of yours (maybe because that’s your standard-meridian), then:
After the tip, the initially-top-point of the sphere with a great-circle coinciding with the circumference of your circular dial-plate will have equatorial-coordinates of: (Lat+DeltaLat, 7). After that, it’s exactly as I said. On Sun, Apr 9, 2023 at 14:09 Steve Lelievre <steve.lelievre.can...@gmail.com> wrote: > > On 2023-04-08 8:52 p.m., Michael Ossipoff wrote: > > I know you said you wanted a link, not instructions, but people have been > suggesting how to achieve dial-autocorrection to Local True Solar Time > (LTST) at the standard-meridian, instead of one’s own meridian. So I felt > that it would be justified to comment about it. > > Michael, > > To me, your case seems to be a specific instance that is covered by the > general case - have I missed something? > > As things stand, I think I know the math involved because I have from the > article by Fred Sawyer that I mentioned in a previous email. It describes > the solution for the general case - we start with a dial at some latitude > and longitude that shows the solar time at some other longitude, which may > or may not be zero offset. We want to move it to a new latitude and > longitude and to show the solar time at some new 'other' longitude, which > may or may not have zero offset from the new location. As well, the article > by Fabio Savian, mentioned in his post, also discusses dial relocation. > (BTW, for NASS members, Fabio only mentioned his article in its Italian > version, but as well he kindly provided an English equivalent which was > included in the most recent issue of the Compendium) > Everyone, > > Since I'm writing this post, I'll take the opportunity to mention that I > have made a couple of small adjustments to my online wedge calculator, > gnomoni.ca/wedge . My thanks go to Roderick Wall for helping me make it > better for the southern hemisphere. Please let me know if you spot any > issues. > > > Steve > > > >
--------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
