haniyyah rashid student id: 4090466. although the form of a sunrose is particularly aesthetically...
TRANSCRIPT
SUNROSE
Haniyyah RashidStudent ID: 4090466
CA
LCU
LATIO
NS
Although the form of a sunrose is particularly aesthetically pleasing, for me, the accuracy of the model was of priority. Because of this, I used the computer generated sun-path diagram on the base. This became a tool with which to check the measurements of each piece and spacing when it came to the final construction.As I was unable to retrieve a sun path diagram for the 21st of every month, it became apparent that the most inaccuracy would occur when locating this date upon a spherical projection with month lines portraying the 1st of each month.
This caused the most problem when creating a sunrose representing the sun’s path during the equinox, as the sun’s path upon each solstice is shown along the vertices of the hour lines, and so being easier to identify.
Spherical Projection, Nottingham
Initially, I would interpolate between the appropriate altitude lines upon the spherical projection, and then measure from this point to the centre of the diagram. Although perfectly reasonable, when it came to producing two sequential triangles that were only very slightly different in base length ‘a’, my slight errors in measuring meant that that the differences between these triangles was not noticeable. I felt it necessary to be more precise with this measurement (as this length also affects the calculation length ‘o’ and ‘h’).
This is why I decided to determine the length from the centre of the sun-path diagram to each of the concentric altitude lines, and keep these values consistent for every triangle. Therefore, at the very least, keeping the human error in measuring consistent amongst each piece!
In an attempt to overcome this, I concentrated on the accuracy of the other measurements. Using the altitude value generated on www.squ1.org.uk/Solar_Position_Calculator, the base length, ‘a’, could be calculated through interpolation between the concentric altitude circles.
θ
h
a
o
Θ – angle of altitude at specific hour
CA
LCU
LATIO
NS
9.1cm
Example calculation:
Summer solstice – 21st June – 10.00am
Nottingham: Latitude: 52.58° Longitude: -1.10°
Altitude: θ = 52.29°Azimuth: 128.4°
Length from centre of diagram to 50° altitude line = 5.7cmLength between 50° and 60° altitude line = 1.3cm
Interpolate: (1.3 ÷ 10) x 2.29 = 0.2977a = 5.7 – 0.2977 = 5.4023a = 5.40cm
Tanθ = o/a Cosθ = a/ho = 5.4023tan52.29° h = 5.4023 ÷ cos52.29°o = 6.98723... h = 8.83212...o = 6.99cm h = 8.83cm
CA
LCU
LATIO
NS
Using a compass from the centre of the spherical projection, I was able to mark length ‘a’ on the appropriate hour line for each individual piece. This meant that I did not have to mark the azimuth angle along the outer edge of the diagram, as this would have been difficult to do accurately. However, I did use the known azimuth angle to ensure that each marking was done correctly.
Sticking the actual triangles onto the base did not prove to be too much of a problem. I used a strong adhesive, and a set square to ensure each piece was as perpendicular as possible. The taller pieces did tend to want to lean to one side. However, by taking these pieces off and re-gluing them down with an extra amount of glue seemed successful enough to solve this problem.
Because of the thickness of the card that was used, the centre of the model became messy as each all of the triangles would not have met at a neat point. Because of this, 1cm was trimmed off of the point of each triangle.
When drawing out each triangle, I used a protractor to measure the angle of altitude, as well as using trigonometry to calculate both lengths ‘a’ and ‘h’. The reason for obtaining all of these measurements was to be able to check the accuracy of each triangle, and was a method in which any errors could be found prior to gluing.
CO
NSTR
UC
TIO
N
Time Azimuth (degrees)
Altitude (degrees)
a (cm)
o (cm)
h (cm)
04.00
51.5 1.42 9.20 0.23 8.20
05.00
62.99 9.08 8.99 1.44 9.10
06.00
74.14 17.54 8.60 2.72 9.02
07.00
85.43 26.49 8.10 4.04 9.05
08.00
97.51 35.59 7.29 5.22 8.97
09.00
111.36 44.39 6.42 5.22 8.98
10.00
128.14 52.29 5.50 7.11 8.99
11.00
250.33 58.24 4.73 7.64 8.99
12.00
177.19 60.81 4.35 7.79 8.92
13.00
204.64 59.09 4.64 7.74 10.97
14.00
227.66 53.67 5.31 7.22 8.96
15.00
245.56 46.07 6.28 6.52 9.05
16.00
259.91 37.38 7.20 5.50 9.06
17.00
272.25 28.31 7.94 4.28 9.09
18.00
283.64 19.30 8.58 3.00 9.09
19.00
294.78 10.71 9.20 0.46 9.21
Summer Solstice21st June
Sunrise: 03.47Sunset: 20.24
NO
TTIN
GH
AM
52
.58
°, -
1.1
0°
NO
TTIN
GH
AM
52
.58
°, -
1.1
0° Equinox
21st March/ September
Sunrise: 06.12Sunset: 18.10
Time Azimuth (degrees)
Altitude (degrees)
a (cm)
o (cm)
h (cm)
07.00
99.82 7.11 9.05 1.13 9.12
08.00
112.27 15.85 8.70 2.47 9.04
09.00
125.81 23.81 8.25 3.65 9.02
10.00
140.96 30.43 7.80 4.58 9.05
11.00
157.95 35.06 7.40 5.19 9.04
12.00
176.36 37.09 7.22 5.46 9.05
13.00
164.95 36.18 7.27 5.32 9.00
14.00
147.31 32.49 7.60 4.84 9.01
15.00
131.45 36.56 8.09 4.04 9.04
16.00
117.35 19.05 8.57 2.96 9.07
17.00
104.54 10.55 8.91 1.66 9.06
18.00
92.46 1.56 9.20 0.25 9.20
NO
TTIN
GH
AM
52
.58
°, -
1.1
0° Time Azimuth
(degrees)
Altitude (degrees)
a (cm)
o (cm)
h (cm)
09.00
138.94 4.22 9.12 0.67 9.15
10.00
151.78 9.39 8.99 1.49 9.11
11.00
165.38 12.72 8.80 2.00 9.02
12.00
1.79.46 13.92 8.75 2.17 9.02
13.00
193.56 12.89 8.80 2.01 9.03
14.00
207.21 9.72 8.95 1.53 9.08
15.00
220.1 4.67 9.18 0.75 9.21
Winter Solstice21st December
Sunrise: 08.20Sunset: 15.43
NO
TTIN
GH
AM
52
.58
°, -
1.1
0°
Summer Solstice, 21st JuneEquinox, 21st March/SeptemberWinter Solstice, 21st December
The difference in number of triangles is very prominent across the sunroses. The number of spaces in between the triangles is what gives us the information. If the lines representing the sunrise and sunset were to be drawn onto this model, then the number of triangles would directly represent the number of daylight hours that we experience on each particular day. Hence, we can see that during the Summer solstice, we encounter around 17 hours of daylight, and on the Winter solstice, the Sun is visible in the sky for about 7 hours. Upon each equinox, we experience an equal number of day lit and night hours (12 hours).
In addition, the models clearly portray the varying times of the rising and setting sun on these key dates in the year. This is easiest to see from the angles creates by the end triangles. The equinox sunrose shows a 180° angle, telling us that the length of day and night is equal. The relatively expansive blank space on the Winter solstice model is a representation of the short day. To see the drastic difference between these times on the Summer and Winter solstice, in 3D form, reiterates how the lengths of our day change throughout the year.
Summer Solstice
Equinox Winter Solstice
From this angle, we can see the difference in altitude of the Sun during the day, not only noting this from the height of the model, but also the distance between the edge of the sun-path diagram and the back of the 3D form. Here is an advantage of applying the triangles directly onto a spherical diagram.
These observations tell us that upon the Summer solstice, the altitude of the Sun becomes very high relative to that in Winter. We know that this is because the Earth’s northern hemisphere is tilted towards the Sun during our Summer months; and tilted away from the Sun during the Winter months.
In terms of architectural design, these angles are vital in our understanding of the interplay between sunlight and designed spaces. We can learn the depth of reach of the sunrays into buildings, as well as their direction. Not only is the sunrose model a representation of the sun’s path, it can also be a tool to help visualise the direction of the sun’s rays upon architecture, and it’s movement throughout the day and year, leading to the design of windows and shading devices accordingly.
By looking at the equinox sunrose, the angle of it’s inclination tells us about the latitude of Nottingham (if we did not know already). We know that, at the equator, the latitude at noon would be 90°. As an estimate, we could say that the angle of this sunrose is approximately 35°. As the altitude = 90 – latitude, we could estimate the latitude of Nottingham to be about 55°, which could be correct.
Summer Solstice
Equinox Winter Solstice
The volume created by this 3-dimensional form gives an immediate impression of each day. The large mass of the Summer solstice sunrose gives the visual impression of a sun filled day, whereas the Winter solstice sunrose gives an instantaneous impact of a much darker day. Here is an advantage of the sunrose model, as, even with little knowledge of the calculations involved, one can still gain relevant information. Immediate analysis is much more easily achievable from this clear 3D form.
Summer Solstice
Equinox Winter Solstice
DU
BA
I 2
5.2
°, 5
5.3
°
To better understand the effect that latitude has on the sun’s path across our sky, I decided to create an equinox sunrose for Dubai.
DU
BA
I 2
5.2
°, 5
5.3
°Time Azimuth
(degrees)
Altitude (degrees)
a (cm)
o (cm)
h (cm)
06.00
93.87 7.58 8.83 1.18 8.91
07.00
100.73 21.03 8.28 3.19 8.87
08.00
108.98 34.15 7.33 4.97 8.85
09.00
120.21 46.51 6.08 6.41 8.84
10.00
237.52 57.14 4.79 7.42 8.83
11.00
165.16 63.78 3.90 7.92 8.83
12.00
199.17 63.25 3.98 7.89 8.83
13.00
225.3 55.88 4.94 7.29 8.80
14.00
241.55 44.93 6.26 7.26 8.84
15.00
252.25 32.43 7.48 4.75 8.86
16.00
260.24 19.25 8.38 2.93 8.88
17.00
266.99 5.77 8.88 0.90 8.86
Equinox21st March/ September
Sunrise: 05.26Sunset: 17.25
We can see that both locations are located in the Northern hemisphere, as the sun’s path at midday is in the south. Once again, as it is the equinox, the sun rises due East and sets in the WestOnce again, if we look at the two different equinox models as if we do not have much prior knowledge of the logistics of the sun’s path, one could mention that the sunrose for Dubai seems to be more densely built up. This would automatically suggest that the climate at this time of year would be quite sunny and warm. Although this model is not to be used for the representation of the quality of light in a given time or area, we can still gain an instant insight into the daylight conditions.If we compare the sunroses with a more logical approach, we can see that the altitude of the sun is generally a lot higher in Dubai than in Nottingham. As the sun rises directly in the East and sets in the West, the path is seen to be a lot more linear across the sky. We can also tell that, in the Summer, the sun would almost be directly overhead. The higher altitudes is down to Dubai having a lower latitude (being closer to the equator than Nottingham).
Nottingham Dubai
These changes in angles will alter our design strategies in architecture. Although direct sunlight will be directed towards the southern facades of buildings, the different altitudes of the sun may result in deeper shading canopies in Nottingham than in Dubai for example (as the sun travels in a more overhead path in Dubai).Also, the higher altitudes in Dubai mean that the length of shadows cast by buildings are shorter than in Nottingham, again, another factor worth considering in architectural design.
The sunrose is a great tool to enhance an understanding of the Earth’s movement relative to the sun. A lot of information can be absorbed from looking at such a model with great ease and speed. The sunrose is most effective when comparing different days of the year or location, as the 3-dimensional forms can be visually linked a lot more easily than by just looking at the spherical sun-path diagram alone.
I feel as though I have made the most accurate model that I possibly could have by hand. However, if I were to create a sunrose starting with a larger print of the spherical projection, the calculations and measurements would have been a great better.
http://www.travelportal.info/general-travel-info/maps-route-planners/maps
BIB
LIO
GR
APH
Y
http://www.squ1.org.uk/Solar_Position_Calculator