Re: The duration of the year

Doug, I didn’t answer your second question: "Assuming that in 1850s I had access to a good transit telescope, and a reasonable clock (daily errors about 1 second a day), how would I refine the quarter of a day into several decimal places?” The formula is: Year = (1 day – transit time

Re: Genuine or not?

The sundial mentioned by Dan Uza is a diptych made in recent years in imitation of those manufactured in eighteenth century in Europe. Sundials of this type are sold in some specialized shops (very few) in Italy and France. On the dial, at top, is written the name GUAYTAMELLI , that is the name of

RE: Genuine or not?

This sundial seems too fanciful to me, with the ship, the Latin motto, and the green foliage (that looks like a dancing cactus to me!) to be an actual copy of an earlier one. It is 20th century, but I don’t know from the photos if it is circa 1920. It could be some sort of souvenir from a

Re: Genuine or not?

Compass doesn't look quite right - if it's German I might expect East to be written as Ost. *Patrick Vyvyan* *Presidente* *Corporación Cultural de Putaendo* On 20 February 2017 at 12:22, Michael Ossipoff wrote: > It doesn't seem genuine to me. > > It isn't just

Re: Genuine or not?

It doesn't seem genuine to me. It isn't just that there doesn't seem to be a way of moving the upper end of the string to the other latitude-marks. It's also that you can't just change the angle of the gnomon, for a different latitude, and use the same hour-lines. So there seems to be no purpose

Genuine or not?

Hello! There's a diptych sundial on sale for about 80 euros supposedly dating from 1920. Do you think this is genuine? I think it is a modern replica. http://anticariatulnou.ro/diverse/antichitati-artizanat-colectionabile/cadran-solar-cu-busola-antica-din-lemn-diptic.html The string does not