Does anyone have any pictures to share showing
the "dial" when illuminated by the Sun?
Can the designer and/or builder of the piece be contacted for information?
Mac Oglesby
In my opinion the object shown in the image is
not a sundial, that is it doesn't serve to mark
the hours.
Moreover I don't believe that it is possible to
obtain the value of the azimuth of the wall only
from this photo.
The upper curve cannot be the hyperbola of the
winter solstice in a sundial facing East since
it is too bent and it passes almost exactly
through the foot of the orthostyle.
In a sundial facing East the foot of the
orthostyle passes through the equinoctial line
and the hyperbola passes more high.
The curves that seem arcs of circle cannot be
compared to hour lines - that are practically
rectilinear segments (in facing East sundials).
The lower curve looks like the summer solstice
hyperbola in a East sundial , but it seems
too far from the orthostyles foot (for
Latitude around 40° as New York)
Probably the object is a game of shades that in
particular instants produce sketches , shapes
and silhouettes .
The fretworked plates (that can produce shades
with particular shape) are all orthogonal to the
wall and placed vertically (their planes are
vertical) and therefore can be illuminated
completely only when the Sun is on the horizon
and their shadows become segments when the
Sun is exactly in front of the wall (thing that
suggests a wall facing South) .
Best
Gianni Ferrari
----- Original Message -----
From: <mailto:[EMAIL PROTECTED]>Robert Terwilliger
To: <mailto:[email protected]>'Sundial Mailing List'
Sent: Friday, June 30, 2006 3:37 AM
Subject: Is this a sundial?
The "sundial" in this photo was submitted to the NASS Register.
Do you think it's a sundial? How would it work?
<http://sundials.org/test/york.htm>http://sundials.org/test/york.htm
Bob
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