Post on 18-Feb-2018
transcript
7/23/2019 I- The Movement of the Sun in the Sky Dome
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THE SUN PATH
• THE VISIBLE PART OF THE SKY FROM ANY
LOCATION
IS CALLED THE SKY DOME
• THE POSITION OF THE SUN
CHANGES IN THE SKY DOME FOR
•DIFFERENT TIMES OF THE DAY
•DIFFERENT TIMES OF THE YEAR AND
•FOR DIFFERENT LATTITUDES
• THE POSITION OF THE SUN IN ALL THESE
PARAMETERS HAS BEEN MAPPED IN THE
SUN PATH DIAGRAM
1
7/23/2019 I- The Movement of the Sun in the Sky Dome
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THE SUN MOVEMENT AT DIFFERENT TIMES- THRU ONE DAY
2
7/23/2019 I- The Movement of the Sun in the Sky Dome
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THE SUN MOVEMENT AT A GIVEN TIME - THRU ONE YEAR
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7/23/2019 I- The Movement of the Sun in the Sky Dome
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BECAUSE OF THE TILT OF THE EARTH’S AXIS
THE SUN POSITION
IN THE SKY DOME KEEPS CHANGING THRU THE
YEAR
WHEN THE SUN SHINES OVER THE TROPIC OF CANCER
WE HAVE SUMMER IN THE NORTHERN HEMISPHERE
AND WHEN THE SUN SHINES OVER THE TROPIC OF CAPRICORN
WE HAVE WINTER IN THE NORTHERN HEMISPHERE
LET US EXPLORE A FEW EXAMPLES FOR SUN POSITIONS IN4
7/23/2019 I- The Movement of the Sun in the Sky Dome
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IMPORTANT DATES
GIVENT THIS CYCLICAL NATURE, THERE ARE FOUR IMPORTANT
DATES TO REMEMBER WHEN CONSIDERING SOLAR POSITION:
• Summ! S"#$%&' 22 D'( SOUTHERN HEMISPHERE
• 22 )u*( NORTHERN HEMISPHERE
SUN IS AT ITS HIGHEST NOON ALTITUDE
• Au%um* E+u&*" 21 M!( SOUTHERN HEMISPHERE
• 21 S.( NOTHERENHEMISPHERE
SUN RISES DUE EAST, SETS DUE WEST
• W&*%! S"#$%&' 21 )u*( SOUTHERN HEMISPHERE
• 21 D'( NOTHERN HEMISPHERE
SUN IS AT ITS LOWEST NOON ALTITUDE
• S.!&*/ E+u&*" 21 S.( SOUTHERN HEMISPHERE
• 21 M!( NOTHERN HEMISPHERE
THE SUN RISES FROM DUE EAST 0 SETS DUE WEST(
ALTITUDE ANGLE OF THE SUN DEPENDS ON THE LATITUDE
3N
3S
EUATOR
7/23/2019 I- The Movement of the Sun in the Sky Dome
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SUN POSITION ATSOLSTICES
AT O EUATOR
5
1( THE CURVEDDOTTED LINE IS THE S6Y DOME
2( THE BLAC6 SOLIDSTRAIGHT LINE
DEPICTS THEMOVEMENT OF THE SUN ON 21ST MARCH WHEN IT ISSHINING OVER THE EUATOR
3( THE STRAIGHTDOTTED LINESSHOW THEMOVEMENT OF THE SUN AT ALL
OTHER TIMESWHICH WILL BE
7/23/2019 I- The Movement of the Sun in the Sky Dome
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SUN POSITION ATSOLSTICES
AT O EUATOR
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1( THE SUN ISDIRECTLYOVERHEAD ON21ST MARCH
2( SHINING OVER T(O(CANCER IT ISLOWER IN THENORTHERNHEMISPHERE
3( AND WHEN OVER THE T(O(CAPRICORN ITIS IN THESOUTHERN
HEMISPHERE
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 1 NORTH
8
AT 1NORTH, THESUN WILLGENERALLYAPPEAR TO
LIE TOWARDS THESOUTHERNS6Y
IT WILLPASSOVERHEAD TWICE A YEAR ON ITSWAY TO AND
FROM THEE UATOR
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 2 NORTH
9
AS WEAPPROACH THE TROPIC
OF CANCER, THE SUNWILL APPEARALMOSTOVERHEADAROUND 21
)UN WHEN ITSHINES OVER TROPIC OFCANCER
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 3 NORTH
1
AT 3 NLATITUDE THE SUNWILL ALWAYSBE IN THESOUTHERNS6Y ATNOON(
THE DOTTED
STRAIGHTLINE SHOWS THE SUNSPATH DURING THAT DAY
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 5 NORTH
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NOTICE THAT
THE SUN PATHPASSES THRU THE CENTREWHEN IT ISSHINING AT THE EUATOR
0ON 21ST )UNEAND 22 DECITS PATH ISPARALLEL TO THAT ON 21ST
MARCH
THE SUMERDAYS AREGETTINGLONGER AND
THE WINTERDAYS ARE
7/23/2019 I- The Movement of the Sun in the Sky Dome
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SUN POSITION ATEUINO;ES
AT O EUATOR
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AGAIN STARTINGAT THE EUATORLET USUNDERSTAND THESUNS PATH THRU THE YEAR ASSEEN IN THESOUTHERN
HEMISPHERE
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 1 SOUTH
13
MOST TIMESOF THE YEAR THESUN WILL
APPEAR IN THENORTHERNS6Y
IT WILL BEIN THESOUTHERNS6Y DURINGITS )OURNEY TO THE TROPIC OFCAPRICORN
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 2 SOUTH
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7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 3 SOUTH
1
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT SOUTH
15
THE SUNWILL ONLYAPPEAR IN THENORTHERN
S6Y E;CEPTEARLYMORNINGAND LATEEVENINGS IN THE SUMMERMONTHS ASSEEN BY THEDOTTEDLINEFROM22DEC
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 5 SOUTH
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THE
ANTARCTIC
CIRCLE LIES
AT 66*S
IF YOU DRAW THE FULLEARTH CIRCLEAS SEEN BY THE CURVEDDOTTED LINE, YOU WILLNOTICE THATON 22 DEC
THERE ISHARDLY ANY<NIGHT
WHILE ON THE 21ST OF
)UNE THE SUNIS VERY LOW
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 8 SOUTH
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NOTICEHOW THE
SUNNEVERSETS ON THE 22ND OFDECEMBE
R BUTROTATESAROUND THE S6Y>
AND IN
MAY,)UNE, )ULY ,AUGUST THE SUNIS NOTVISIBLE
AT ALL(
7/23/2019 I- The Movement of the Sun in the Sky Dome
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AT 9 SOUTH
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AT THE
SOUTHPOLE THESUN ISROTATINGAT THEHORI=ON
ON 21ST MARCH
0ROTATINGVERY LOWIN THE S6Y
ON 22ND DECEMBER(
IT IS NOTVISIBLE ATALL FROMAPRIL TO
7/23/2019 I- The Movement of the Sun in the Sky Dome
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UDERSTANDING THE S6YDOME
2
THE SUN AS IT MOVESACROSS THE S6Y DURING THE DAY AND ACROSS THE SEASONS OF THE YEAR ARE INDICATEDHERE ON THE S6Y DOME
IF THESE PATHS AREVIEWED IN PLAN WE GET
OUR SUN PATH DIAGRAMFOR A GIVEN LATITUDE(
7/23/2019 I- The Movement of the Sun in the Sky Dome
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THE SUN ALWAYS MOVES AROUND
THE CENTER OF THE S6Y DOME
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TWO IMPORTANT VALUES ARE READ OFF THE SUN PATHDIAGRAMFOR A GIVEN LAITITUDE:
1( THE AZIMUTH ANGLE &(( %? ?"!&@"*%# */# "* %??"!&@"*
m$u! '#"'&$ !"mNORTH2( THE ALTITUDE ANGLE &(( %? !%&'# */# %? $u*m$ %" %? /!"u*