.
SAMPA Calculator
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Solar and Moon Position Algorithm (SAMPA)
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Solar and Moon Position Algorithm
» SAMPA Calculator
SAMPA Calculator
Compute the Sun & Moon position and eclipse irradiance reduction from time
and location using NREL's
Solar and Moon Position Algorithm (SAMPA)
.
Required input values:
Enter start date:
Year:
Month:
January
February
March
April
May
June
July
August
September
October
November
December
Day:
1
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5
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31
Enter end date:
Year:
Month:
January
February
March
April
May
June
July
August
September
October
November
December
Day:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Enter output time interval:
Interval:
1
2
5
10
15
30
60
Units:
Second
Minute
Enter site location information:
Observer latitude (negative south of equator) [degrees]
Observer longitude (negative west of Greenwich) [degrees]
Observer time zone (negative west of Greenwich) [hours]
Observer elevation [meters]
Annual average local pressure [millibars]
Annual average local temperature [degrees Celsius]
ΔUT1
= Universal Time (UT) - Coordinated Universal Time (UTC) [seconds]
ΔT
= Terrestrial Time (TT) - Universal Time (UT) [seconds]
Optional input values:
Atmospheric refraction at sunrise and sunset [degrees]
Total column ozone thickness [cm] (for Bird Model)
Total column water vapor [cm] (for Bird Model)
Broadband aerosol optical depth (for Bird Model)
Forward scattering factor (for Bird Model)
Albedo [ground reflectance] (for Bird Model)
Solar constant [W/m
2
] (for Bird Model)
Check desired final output values:
Area of sun's unshaded lune† [degrees squared]
Percent area of sun's unshaded lune† [percent]
Estimated direct normal irradiance [W/m
2
] (from
Bird Model
)
Estimated direct normal irradiance from sun's unshaded lune† [W/m
2
]
Estimated global horiz irradiance [W/m
2
] (from
Bird Model
)
Estimated global horiz irradiance from sun's unshaded lune† [W/m
2
]
Estimated diffuse horiz irradiance [W/m
2
] (from
Bird Model
)
Estimated duffuse horiz irradiance from sun's unshaded lune† [W/m
2
]
Check desired intermediate output values:
Solar topocentric zenith angle [degrees]
Solar topocentric azimuth angle (eastward from north) [ 0 to 360 degrees]
Solar topocentric azimuth angle (westward from south) [-180 to 180 degrees]
Lunar topocentric zenith angle [degrees]
Lunar topocentric azimuth angle (eastward from north) [ 0 to 360 degrees]
Lunar topocentric azimuth angle (westward from south) [-180 to 180 degrees]
Local observed topocentric angular distance between sun and moon centers [degrees]
Radius of sun disk [degrees]
Radius of moon disk [degrees]
† The sun's unshaded lune is the portion of the sun that is not blocked by the moon during a possible eclipse.
Please read the
disclaimer
before using this product.
For more information about
SAMPA and the C source code
For questions about the solar and moon position algorithm contact:
Ibrahim Reda
For questions about this website or the calculator contact:
Afshin Andreas