Dear Jim, Sara et al,
I agree with Sara that the terms 'equatorial dial' and 'equinoctial dial' are
synonymous. I believe that the reason we have two terms is purely historical.
English diallists writing in the 16th 17th centuries were looking back at
armillary spheres which represented the
Dear Roger et al,
I don't think the later middle ages were quite as dark in Europe as you
suggest. Science did make some progress (eg the 'Merton calculators') despite
the disruptions of the various plagues.
For example, the monk Robert Stikford, working at St Alban's Abbey (not far
from
Re the two dials on Braunschweig Cathedral: the dating of these is
extremely problemmatical and I don't believe Zinner's dates - even he
changed his mind!
You are probably right! Zinner has lots of merits with his tremendous
research-work during the pre-computer era, but you are not the only one
Hi all,
Does anyone know what material was used and how thick it is for the vertical
section of the following “ The Tree of Sonius” sundial.
I Rather like the style of this sundial.
http://www.regiomontanus.at/bild40_e.htm
Roderick Wall.
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Roderick,
The material used is steel.
Measured on a sketch of the designers, Jan Kragten en Fer de Vries, the steel
plates have a thickness of 1 cm
The distance between the plates is 3 cm
The slits on the north side are covered with frosted glass on the inside
The sundial is made by a factory
I’m agree to the equivalence of equinoctial and equatorial.
Their origin is different, I think the first refers to the condition when the
temporary hours are equal and the same of modern hours, the second to the
orientation of a dial to get equal angles among hour lines, anyway I’m agree
they
Dear Nicola et al.
Johannes Hommilius oder Johannes Hommel (See f. i. in the German Wikipedia) was
not an unknown German scholar.
For me it is also problematic to say that there was a break between the
Graeco-Roman and the medieval gnomonics. Maybe the river of transmission became
a brook, but
Dear Karlheinz, Certainly Hommilii or Hommel in his time was not an unknown
scholar. In my post I meant to say that his name is quite unknown today in the
history of sundials, unless someone proves to me that the name of Hommilii is
often cited in several books in the modern books. That the
Dear Roger,
I have not been following this thread on Peuerbach closely, but feel it
necessary to challenge two statements:
1) the description of Medieval astronomy and science as impoverished and
dark. While this was a popular view until the mid-twentieth century, this is a
fallacy and
Dear Roger,
Sara's message merits serious study!
We here in Europe weren't totally asleep
in medieval times or even in the so-called
dark ages following the Fall of Rome.
[A fair proportion of Europe seems to be
falling asleep just now but that's not the
period you are referring to :-) ]
There
Sara wrote
By the third century BC there were so many of them that people complain about
having to run their lives by these blasted timepieces.
I guess this is her source
Titus Maccius Plautus 254 - 184 BC - a influential Roman playwright of comedies
- is quoted, in 'Attic Nights' by
The 'river' of knowledge from the ancient world to medieval Europe flowed,
in large part, through the Islamic world, which had appropriated much of
the ancient learning. However, not all ancient learning arrived in the West
in this way. For example, the important Archimedean treatises* On the
Good question. I found that a "hemispherical" (I put it in quotes
because the mirror I use actually has an essentially ellipsoidal
cross-section about the axis of rotation) mirror was needed to
observe the entire day's travel of the sun in midsummer. There's an
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