Dear friends,
a new issue of the Italian magazine Orologi Solari is available for
download from the usual site http://www.orologisolari.eu/.
Here is the list of articles together with a short abstract:
1. "The conical sundials of Antiquity. Generalities - Part II" by Albéri
Auber Paolo
In the first part the author described conical sundials as they were
conceived and built in antiquity; he then analyzed the effect of an
incorrect evaluation of the latitude of the place and he finally described
the practical process followed for their realization. In this second part
the author proposes an innovative formula that allows us to derive the
project latitude ("intended") following exclusively linear measurements
made on the sundial, together with a well-known formula that provides the
half-width of the cone.
2. "The «shadow schemes» in the Latin Middle Ages - Addenda" by Arnaldi
Mario
In Gnomonica Italiana n. 16 the 'shadow schemes', reported in a large
number of medieval Latin manuscripts, were illustrated and listed by
Karlheinz Schaldach. This article does not add anything new to the dividing
method of the various models described in that article, but it enriches the
list of handwritten testimonies with new texts recently found by the author.
3. "A sundial on two faces of a cube" by Arioni John
A clock built around the geometry of the cube is presented, consisting
essentially of two intersecting quadrants, with each quadrant providing the
shadow to the other for reading the time and season.
4. "Refraction and depression at the horizon" by De Donà Giuseppe
The author reports the results obtained over the years by timing the
instants of sunset on the sea and he compares them with the theoretical
values provided by the formulas available in the literature. Thus he comes
to the conclusion that although these can provide a reliable result in
"normal" evenings, there are exceptional situations in which the phenomenon
has a completely unexpected evolution.
5. "The Sunshine recorder" by Gunella Alessandro
The author describes an old instrument used in meteorological observatories
to record the hours of the local sunshine, basically a cylindrical polar
sundial. The gnomon is a glass sphere which focuses the light and burns a
‘line’ through a piece of treated paper.
6. "Who invented the Oughtred diagram ?" by Gunella Alessandro
The author in this article recalls a "portable" sundial by Schoener, which
identifies hours using only the Azimuths: a diagram that appears 90 years
before the so-called Oughtred diagram. The article also explains how
Schoener indirectly applied the operating method called DATSÜR to build the
diagram.
7. "Johan Peterson Stengel: GNOMONICA UNIVERSALIS" by Gunella Alessandro
In this article, the author introduces the work of Johan Peterson Stengel
GNOMONICA UNIVERSALIS, a true encyclopedia of graphic Gnomonics, that he
has translated to Italian. The translation is offered as a Bonus starting
from this issue.
A digital bonus can also be downloaded for additional reference material.
Hope you will enjoy the reading, although in Italian only.
Ciao.
Gian
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