"Mike Cowham" <[EMAIL PROTECTED]>
References: <[EMAIL PROTECTED]>
Subject: Re: Earliest Sundials
Date: Mon, 10 Jan 2005 10:09:32 +0100
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Reply-To: "Frans W. Maes" <[EMAIL PROTECTED]>
Dear Mike and all,
I am sorry that I could not respond earlier. Last year I wrote an article
about a related question, from which I have some relevant information.
1) The earliest evidence for pole-style dials in Europe.
The only author who did extensive research in archives of monasteries,
libraries etc. is Zinner, I think. In "Deutsche und Niederlaendische
Astronomische Instrumente des 11.-18. Jahrhunderts" (1956) he mentions a
folding sundial from 1417 (p. 55). One part unfolded in the equatorial
plane, so that its edges pointed to the celestial pole. This dial was
reported by Georg Hartmann in 1544, as Zinner wrote. I guess it does not
exist anymore.
Zinner found manuscripts giving instructions for the construction of
pole-style dials from 1426 onward (p. 56). So my conclusion is that the
pole-style principle appeared in Europe around 1400.
2) The Arabic connection.
The sundial at the Umayyad mosque in Damascus from 1371 (mentioned in
earlier postings) has been described by Louis Janin in Centaurus 16 (1972),
p. 285-298. It incorporates three sundials. The one for equal hours uses a
pole-style. It is a high-point of Arabic gnomonics, and apparently the
result of a long tradition. So the pole-style principle was known to the
Arabs long before 1371, but was only used by astronomers.
The odd story of this sundial: the Egyptian astronomer At-Tantawi noted in
1876 that it was not level and not properly aligned anymore. When he tried
to correct this, the marble dial face (1x2 meter) broke. He made a copy,
which is quite accurate, as is apparent from comparison with three large
pieces of the original. These are now in the National Museum in Damascus.
3) Was the pole-style principle brought to Europe from Arabia, for instance
by returning crusaders?
Karlheinz Schaldach, in BSS Bulletin 1996 nr. 3, p. 32-38, thinks not. He
gives 3 arguments:
a) The first Latin author (or at least one of the first) writing on the
construction of equal-hour sundials, gives no hint that he obtained any
ideas from Islamic contemporaries.
b) There are almost 100 texts on sundials of the 14th and 15th centuries,
proving a great effort in understanding sundial principles, but none giving
the correct solution of the pole-style.
c) There are some 'sun-trials' from that period, showing a 'trial and error'
process.
4) What is the oldest still existing pole-style dial?
a) Fixed dials.
My article addressed the question: What are the oldest, dated or datable,
fixed sundials? It appeared in the Bulletin of the Dutch Sundial Society
2004 nr. 1, p. 15-18, and nr. 2, p. 25-29. The focus was on the sundial at
St. Jacob's Church in Utrecht (NL), which is dated 1463. Zinner, in his
extensive catalog "Alte Sonnenuhren an Europaeischen Gebaeuden" (1964) gives
in the introduction a list of 27 modern sundials of the 15th century. With
'modern' he means reading equal hours, which implies a pole-style. Utrecht
is nr. 7 in this list. With help of Karl Schwarzinger, who takes care of the
Austrian database, and Willy Bachmann, who maintains the database of German
sundials, I was able to check the list, remove some and add some others, and
to get pictures of each. My list of the six oldest dials is as follows:
1446, Weissenfels (Germany), carved in stone, dated
1447, Klosterneuburg (Austria), carved, dated
1452, Hall (Austria), painted, datable
1454, Waldhausen (Austria), carved, dated
1457, Duderstadt (Germany), carved, dated
1463, Utrecht (Netherlands), carved, dated.
'Datable' means: a reliable written source exists, and the stylistic
appearance of the sundial fits the period.
The list should be considered with some reserve, though. Dated medieval
sundials (with a horizontal rod as gnomon) may have been upgraded to a
pole-style dial later, or the carved date may have been changed at later
restorations. Also, documents may surface some day documenting an earlier
date for undated dials.
b) Portable dials (travel or table-top).
I have not researched this question. Karl Schwarzinger sent me a pretty
folder with color pictures of many beautiful Austrian sundials. Among these
is a folding dial ('Klappsonnenuhr') from 1451, possibly made by Georg
Peuerbach and now in the Kaiser Maximilian Museum in Innsbruck. Does anyone
know of an older portable dial? Maybe Mike's new book "A Dial in Your Poke"
tells everything about it!
Best regards,
Frans Maes
53.1N, 6.5E
www.fransmaes.nl/sundials/
----- Original Message -----
From: "Mike Cowham" <[EMAIL PROTECTED]>
To: "SUNDIAL" <[email protected]>
Sent: Friday, December 24, 2004 4:38 PM
Subject: Earliest Sundials
Dear Sundial Friends,
I am trying to find the earliest evidence for sundials made in Europe
with gnomons aligned to the Earth's axis. They were commonly in use after
about 1550, (e.g., Nuremberg diptych dials), but I believe that there are
much earlier ones. Rohr, in his book, believes that the technology probably
came to Europe from the Arabs following the crusades, the last of which
finished around 1290.
One string gnomon dial is illustrated by Zinner that he believes was
made by Regiomontanus in 1463. Does anyone know of any earlier dials, fixed
or portable using this 'new technology', or any dials with the new gnomon
earlier than 1550?
Best Wishes to all my Sundial Friends for Christmas and the New Year.
Regards,
Mike Cowham
Cambridge UK
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