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© Tony Moss 2006
All of the material in this presentation
originates from the work of
Edward Cholmondeley Middleton
of Birmingham, England
as published in his
1913 instruction book.
A facsimile of this typewritten
work has been published by NASS
I must record my thanks to
Mac Oglesby (NASS) and
Mike Shaw (BSS) for many
sessions of patient proof
reading, additional material,
valuable suggestions
and encouragement.
PowerPoint™ is not a precision drawing program.
It is not always possible to position
lines and points with total accuracy
Any small inaccuracies in the following slides
are mainly due to this fundamental problem.
The delineations described take no account
of longitudinal correction. The dials would
therefore indicate apparent solar time.
This presentation was inspired by the section on the
Middleton Dialling Scales in Frank Cousins’ book
‘Sundials - the Art & Science of Gnomonics’
To assist understanding and to avoid confusion
the same terminology has been adopted in the
slides which follow.
(alpha) The angle between the substyle and the noon line.
(phi) The latitude at which the sundial is located.
(beta) The ‘dial height’ or angle between style and substyle.
H
The hour angle of the plane of the gnomon.
D
The declination of the dial. Negative east, positive West.
The Latitude Scale
The Hours Scale
Scale divided into quarter hours
and five minute intervals
© Tony Moss 2006
Delineating a
horizontal dial
for 55° North
11
12
10
9
8
7
6a.m.
Latitude 55°
© Tony Moss 2006
Noon Line
(morning hours)
12
1
Delineating a
horizontal dial
for 55° North
2
Noon Line
3
(afternoon hours)
4
5
6 p.m.
© Tony Moss 2006
Latitude 55°
6 a.m.
Co-latitude
(35°)
Noon Line
7
8
A vertical direct
south dial for
55° North.
(morning hours)
9
10
11 12
© Tony Moss 2006
6 p.m.
Co-latitude
(35°)
5
4
3
2
12 1
A vertical direct
south dial for
55° North.
(afternoon hours)
© Tony Moss 2006
© Tony Moss 2006
Plotting a Vertical Dial at 50° 30’ North
Declining 22° West.
(morning hours)
Style Height
angle = 36.14°
9
1hr.
(by calculation)
Style Height (
) = 36.14°
Angle between Sub-style
& Noon Line ( ) = 17.161°
10
1hr.
11
Hour Angle of the Plane of the Gnomon
Angle ‘H’ = 27.636° = 1hr 50m 33secs.
12
1
50m 33secs
Substyle Line
at 17.161° to
vertical.
© Tony Moss 2006
Plotting a Vertical Dial at 50° 30’ North
Declining 22° West.
(afternoon hours)
Style Height
angle = 36.14°
7
1 hr.
1 hr.
8
6
1 hr.
9
4
10
60m 0secs
- 50m 33secs (H-1hr.)
= 9m 27secs
3
11
12 1
5
1 hr.
1 hr.
9 mins 27 secs
from end of scale
Lindisfarne Dialling Scales
available from
Tony Moss
The Lindisfarne Presse
Dial House
43 Windsor Gardens
Bedlington
Northumberland
01670 823232
tony@lindisun.demon.co.uk
In brushed stainless steel
£25 per pair post free
Heavy duty laminated paper
£6 per pair post free.
A Jester Production
2006