The Angle of Insolation #2
Altitude and Azimuth
Tap the rising sun to begin
How do we identify where the Sun is located?
On a graph we use x and y coordinates to
identify location
(3,2)
But when the Sun is millions of miles away and
not in our atmosphere what we see is all a matter
of perspective
the use of the Earth Science Reference Tables.
Thinking of the sky as a dome above our
heads
helps
identify
thediagram
Sun’sbelow,
location
r answers
to questions
36 us
through
38 on the
which represents
Sunset and midnig
(No appare
pect to Earth’s surface at solar noon on certain dates. The latitudes of six locatio
are shown. The observer is located at 42° N in New York State. The date for th
iberately left blank.
tion
June 21
W
March 21
S
A
E
N
To identify the Sun’s location in this dome we use
angles instead of straight-line distances
(2) sand, silt, and pebbles, only
(3) pebbles
theangles
mixture, only
There
are and
two
that help
(4) sand, pebbles, and the mixture, only
us identify the Sun’s
location as it appears to move through the sky...
diagram below shows the apparent path of the Sun as viewed by an observer at a certain Ea
arch 21.
Sun directly
overhead at
noon
West
Pat
h
of S
un
South
Observer
North
East
ANGLE #1 - Altitude
The vertical measurement from the surface to the Sun
Noon
Sun
to horizon
73°
Remember we used angles to measure the altitude
of Polaris earlier in the year
On diagrams of the Sun’s path, A protractor is
drawn in to help you identify the altitude. Notice,
the maximum altitude is 90º (directly overhead)
76 and 77
Sailor’s Observations on the Deserted Island
70
80
90
80
70
60
60
50
40
40
50
20
30
Jun
20
30
Sun’s
apparent
path
Apparent
position of
Polaris
S
N
E
0
0
10
10
e 21
W
ANGLE #2 - Azimuth
The measurement from the North along the ground to
the direction of the Sun
N
44°
NE
Sailor’s ObservationsW
on the Deserted Island
W
70
80
90
N
60
E
0º
º
30
0
20
270º
EW
º
0
4
2
0
º
2
E
77
78
76
04
Polaris
of
large,position
gaseous,
Apparent
79
03
path
apparent
are
relatively
Sun’s
3 Three planets that
city is slowest on July 5 because
79
and of low density are
osest to Earth
(1) Mercury, Jupiter, and Saturn
e from the Sun is greatest 50
50
(2) Venus, Jupiter, and Neptune
oon, and the Sun are located 60
60
Uranus
t line in space
70 (3) Mars, Jupiter, and
70
0
80
90 Saturn,
(4) 8Jupiter,
and Uranus
aximum temperatures occur in
Sailor’s ObservationsS
on the Deserted Island
Hemisphere
15
0º
180º
2
1
0
º
04
N
1
J
78 Latitude:
N
02
(4)
03
77
01
01
N
1
2
e
nu
(2)
76
78
00
E
90º
S
79
10
WW
N
02
(No apparent motion)
20
10
Sun’s
apparent
and
midnight
path
Apparent
position of
position Polaris
º
00
Sunset
50
position
60
S
0
21
E
e
Jun
W
º
Sunset
E
S
N6
30
(3)
Sunset 78
position
Latitude:
Midnight position
70
30
30
40
50
W
80
40
Top view
S
N
E of
Midnight
position
º
0
3
Azimuth
3
(1)
79
Lab Instructions
Click on the Mr. Sun App
Step 1: Set your location
Make sure
you are in
Larchmont
Step 2: Set your date
Change
the date
Step 3: Find Noon Sun Altitude
Record the
Altitude
(to the nearest whole degree)
Move the slider
until the time
says 12:00
Step 4: Find the Sunrise Azimuth
Record the
Azimuth
(to the nearest whole degree)
Move the slider
until its over
the rise time
Step 5: Find the Sunset Azimuth
Record the
Azimuth
(to the nearest whole degree)
Move the slider
until its over
the set time
Step 6: Use the noon sun altitudes
from each month to create a bar graph
15º
Step 7: Repeat steps 2-6 for the other dates
Step 8: Answer the following questions on
the lines provided on your lab sheet
Questions
1) According to your graph, what is the highest
altitude the sun reaches? what is the date?
2) According to your graph, what is the lowest
altitude the sun reaches? what is the date?
3) How much does the altitude change
from its highest point to its lowest point?
4) What is the Azimuth on the following dates?
What direction is that?
• Dec 21 azimuth ______ Direction ______
• Mar 21 azimuth ______ Direction ______
• June 21 azimuth _____ Direction ______
• Sept 23 azimuth _____ Direction ______
5) Are there any differences between the
information on Mr Sun for 12/21/11 and
12/21/12? If yes what are they?
Congratulations, you are finished!