Transcript The Innovative World of Sundials By Bill Gottesman This is a sundial.

The Innovative World of Sundials
By Bill Gottesman
This is a sundial
But so is this
And this
And this
So is this
So, what is a good framework for thinking
about all these different sundials?
Sundials are all about measuring
the angle of the sun.
But which angle?
Clock time is the same as right
ascension, pretty much.
Adapted From Luke
Coletti’s
www.gcstudio.com
Some Key angles:
Declination
Some Key angles:
Right Ascension
Some Key angles:
Azimuth
Some Key angles:
Altitude
Example
This is the Altitude
Angle, about 60°
This is the Azimuth Angle.
Sun is about 60° West,
giving a shadow 120° East
Actually, at High Noon, the sun is exactly
(South)
south, pardner
Right ascension sundials are the most
common, by far
Adapted From Luke
Coletti’s
www.gcstudio.com
Right Ascension Sundials
Equatorial Armillary Sphere
Right Ascension Sundials
Horizontal with Noon Cannon
Right Ascension Sundials
There
Equatorial,
goes the neighborhood
Delhi
Right Ascension Sundials
Equatorial Scaphe (bowl) dial
Right Ascension Sundials
Non-equatorial Scaphe dial
Right Ascension Sundials
Equatorial Pipe Dial by Kate Pond
Right
Ascension
Sundials
Vertical
by
John Carmichael
Right Ascension Sundials
Vertical, with Point Nodus
Right Ascension Sundials
Horzontal (Kitt Peak Solar Telescope)
Right
Ascension
Sundials
Horizontal
Portable
Right Ascension Sundials
Wheatstone
Polarizing
Right Ascension Sundials
Equatorial
Clock Dial
Right
Ascension
Sundials
Inverted
Equatorial
Right Ascension Sundials
Equatorial
Globe Dial
Right Ascension Sundials
17th century
stained glass dial
This is part of
the artwork:
“Time Flies”
Right Ascension Sundials
Has anyone seen
this dial?
Vertical Dial,
“Singleton”
layoutOld
of Mill,
EquationUniversity
of Time
Of Vermont
Altitude Sundials
Altitude Sundials
A 17th century “Digital” sundial
Altitude
Sundials
Pillar or
Shephard’s dial
Altitude
Sundials
Card Sundial
Altitude
Sundials
Chalice Dial
Altitude
Sundials
Portable
Ring Dial
Azimuth
Sundials
(Gnomons are
vertical)
Analemmatic Dial
(Sun Compass)
Azimuthal Sundials
Where is the Vertical Gnomon?
Azimuthal Sundials
Ta Da
Azimuth Sundials
The
layout
ofthe
an
Where
does
analemmatic
Analemmaticsundial
dial’s
is acome
vertical
shape
from?
projection of a
portable ring dial
Azimuth Sundials
Table sized
Analemmatic
Sundial,
Carved Stone
Azimuthal Sundials
Double Horizontal, Self Orienting
Azimuthal Sundials
Double
Horizontal,
Self
Orienting
Azimuthal Sundials
William Oughtred
Heliochronometers
(Or very accurate sundials that actually tell you what time it is)
Wait a
minute, what
is this
shape?
Here it is again.
It is called the
Analemma, or
the Equation of
Time.
One year of
Photos, taken at
the same (clock)
time each day
Photo by Anthony
Ayiomamitis
Analemma unwound to give the
Equation of Time
Heliochronometers
Ferguson
Heliochronometers
Heliochronometers
Pilkington and Gibbs
But where is the
Figure 8 Analemma?
There is a cam under
this Calendar dial
Heliochronometers
Focusing Equatorial
Sundial
(Made by Yours Truly)
Heliochronometers
2 mirrors cast 2
beams, with a thin
cursor inbetween.
Watch this movie…
Potpourri of Other Remarkable Dials
Civil Time
Equatorial at
Greenwich
Naval
Observatory
Potpourri of Other Remarkable Dials
Digital
Sundial
By Daniel
Scharstein of
Middlebury
College
Potpourri of Other Remarkable Dials
Team Disney
Headquarters
in Orlando
Potpourri of Other Remarkable Dials
Potpourri of Other Remarkable Dials
Modern
Altitude
Dial
“NASS
Angel”
By Fred
Sawyer
(1999)
Potpourri of Other Remarkable Dials
Bifilar dial has
two strings
which cross at
different
heights. Very
verstile, but
complex
mathematics
Potpourri of Other Remarkable Dials
Schmoyer Sunquest.
Can you find the
Figure-of-8
analemma?
Light beam reads civil
time at all longitudes
and latitudes in US, as
well as during daylight
savings.
Potpourri of Other Remarkable Dials
Sawyer Equant
Equinox/Solstice Sculpture (Kate Pond)
Time Lapse movie, day before equinox
Take Home Message
• There are an enormous variety of Sundials
• Despite 4,000 year history, new dials are still
being developed by enthusiasts
• Questions?
Bill Gottesman, 2006