Position of the Sun by
Spreadsheet
for a day
download
Select the
table 'input': |
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Input (red frames): 1) date, month, year Don't modify any other cells. |
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The table calc
performs the calculations, using a lot of auxiliary
variables. It should be neglected. |
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Select elev az to see data and diagrams of elevation and azimuth. | |
Select E o T for
data and diagrams of the Equation of Time. |
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Select declin
dist to see data and diagrams of the
declination and distance. |
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Select orbit to see data and a diagram of the ecliptic orbit. |
The value
"elev" is not taking into account the atmospheric refraction.
Comparing
the results "elev" (airless) of the spreadsheet with (4
decimal places) of HORIZONS
Web-Interface
(NASA JPL) the mean absolute error is only (0,0034 ± 0,0022)°.
Comparing
the azimuth results "az" of my spreadsheet with the 4 decimal
values of HORIZONS
Web-Interface
(NASA JPL) the mean absolute error is (0,0077 ± 0,0024)°.
Diurnal
motion of the Sun on May 19 at 50°N, 10°E:
Diurnal motion of the Sun at 50°N, 10°E:
The equation
of time can by computed (neglecting nutation in longitude)
by
E = L0 - 0.0057183° - RA
EoT = 4*E in minutes
Example: 1991, May 19:
Position of the Sun in the ecliptic plane (1991, May 19):
sun_day.xlsx
(Excel, Windows, Mac) sun_day.ods
(LibreOffice,
recommended, Windows, Mac) |
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Die Zeitgleichung: Eine einfache Formel zu Sonnenaufgang und Untergang General
Solar Position Calculations (PDF) MICA
(Multiliyear Interactive Computer Almanac), US
Naval Observatory USNO Astronomical Applications Department, Sun
or Moon Rise/Set Table for One Year USNO, Apsides
and Seasons |