Dear Friends, the question of the name for each type of sundials is old. When I discovered, on 1994, the gnomonica of Athanasius Kircher, I finf in his book a lots of sundials ever seen! But also a lot of name for the sundials ever read! As, I wrote a little "dictionary" of terms of gnomonica!
Now the question proposed for this simple "equinoctial cylindrical sundial", makes us come back on this argument. Normally, in the gnomonica, the name for a sundial is given from the position of his plane on the celestial sphere. In this case, the sundial have a cylindrical plane positioned in the equinoctial plane. His modern name shoud be: "cylindrical equinoctial sundial with equinoctial gnomon". I find this sundial in the history. Athanasius Kircher described it in his book "Ars Magna Lucis et Umbrae" on 1644 and named it "Horolabium concavum cilindraceum universale" I show in the attached pictures. IN the first drawing, you can see the horolabium (non positioned in the equinoctial plane) for the description of hours line. Here the gnomon is not a vertical style, but the dotted line XY. But in the same drawing (n° 2), I added the perpendicular gnomon at the equinoctial plane, like in the sundial proposed at this sundial list. Obviously, in this case the sundial have a double effect: Equinoctial and Polar plane and the name shoud be "Equinocial-Polar semicylindrical sundial." Hope this is a little help for the question. Thanks, and best wishes, Nicola Severino The cylindrical ---------- Initial Header ----------- >From : sundial-boun...@uni-koeln.de To : sundial@uni-koeln.de Cc : Date : Thu, 20 May 2010 22:45:12 +0400 Subject : Russell Porter Sundial? > Friends, > > Is there a conventional name (like horizontal', equatorial', polar' and so > on) for the sundial constructed as shown below? > > Am I right thinking that the name of this construction is "Russell sundial"? > I mean Prof. Russell Porter, the Palomar Mountain Observatory. > > Any help, please. > > Aleks > www.sundials.ru > > ---------- Initial Header ----------- >From : sundial-boun...@uni-koeln.de To : "????????? ????????" sundi...@mail.ru Cc : sundial@uni-koeln.de Date : Thu, 20 May 2010 18:49:41 -0400 Subject : Re: Russell Porter Sundial? > > I think the dial could be called a Polar dial, but I favor Equatorial, > because the hour marks will be evenly spaced along a cylindrical > surface, typical of many equatorial dials. How about shaking things > up a bit, and calling it a Polar Equatorial? Definitely not > horizontal. > -Bill Gottesman > Aleksandr Boldyrev wrote: > > Friends, > > Is there a conventional name (like horizontal', equatorial', polar' and so > o > n) for the sundial constructed as shown below? > > Am I right thinking that the name of this construction is "Russell sundial"? > I mean Prof. Russell Porter, the Palomar Mountain Observatory. > > Any help, please. > > Aleks > [1]www.sundials.ru > > > ____________________________________________________________ > > [cid:part1.07090803.01090405@comcast.net] > _______________________________________________________________________ > > --------------------------------------------------- > [2]https://lists.uni-koeln.de/mailman/listinfo/sundial >
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