Solar CHARTS
SOLAR
CHART.
DRAWN FOR HONGKONG LAT. 22′′IS: N
TIMES SHOWN ARE FOR MEAN LOCAL TIME (1006114710°E)
HK STANDARD TIME (GH.T.+ 8·00 HRS. J
15 25 MINUTES AHEAD OF MEAN LOCAL TIME TO FIND HR STANDARD TIME ADD 25 MIN TO THE TIMES MARKED ON CHART
e
N
JUNE
21
MARCH 212
E
W.
나날
SEPTEMBER 210
ST
DECEMBER 219
کھر
MARCH 21!
JUNE 215
SEPTEMBER 21
DECEMBER 2
ELEVATION FROM SOUTH
1
DECEMBER 21
JUNE 2/9
MARCH 20
SEPTEMBER 29
ELEVATION FROM SOUTH-EAST
'
E
1
NW.
PLAN
CORRECTIONS FOR EQUATION OF TIME -
21 DEC. - 2 MINS.
21 MAR. +7 MINS
21 JUN + MIN 21 SEP. - 7 MINS
We are grateful to Mr. S. E. Faber, A.F.C., the well known Engineer, for providing us with the Solar Charts which we publish on this page. They are a valuable addition to the all too scanty scientific data available to those whose task it is to build in South East Asia. The only other way in which
DEC
MAR.
SETT
llama
1700 NOON
"Elevation from S.E
100.04
FACING S.W.
JUNE.
"Tp.m.
SHADED
CENTRE OF DIAGRAM.
4
19
N
JUNE 21
MARCH 2,
SEPTEMBER 2
DECEMBER 212
ELEVATION FROM WEST
shadows can be accurately determined is by use of Heliodon, but this is a costly apparatus and involves a fairly lengthy process while these charts are simple and waste no time.
A wider issue is raised here and it is the need for planned research in South East Asia, which would not only cover items such as this but the whole field of building operations.
The Chart shows the position of the sun at hourly intervals of mean local time (i.e. sun time, not clock time) for the three main conditions of midsummer, equinoxes, and midwinter.
To find when the sunshine will reach any particular point of a building detail (e.g. a window cill), place a tracing to any scale of the detail over the appropriate chart, with the point in question at the centre of the circle (or semi-circle) of the chart; and draw a line from the centre touching the outer edge of any portion which shades the point in question (e.g. a hood over the window). The times when the point is not shaded can then be read from the chart.
Tracings of plans of windows, or of building blocks should be placed on the "Plan" at their correct orientation. Tracings of vertical sections should be placed on the appropriate "Elevation", i.e. the one at right angles to the plane of the wall. As an example, the sketch shows a 5 foot window with a hood projecting 1′,6" in front of the plane of the window frame. If it faces South West, the sun will be cut off from the window until 10 past 10 a.m. in December, 10 past 12 noon in March and Sept. and 2 p.m. in June.
By the clock these times will be about half past 10, half past 12, and 20 past 2 respectively, and if Summer Time is in operation, the June and September clock times will be 20 past 3, and half past I respectively.