Google Earth Solar Position Calculator

This calculator determines the solar position (azimuth and altitude) for any location and time using Google Earth's data. Solar position is essential for solar energy applications, astronomy, and environmental studies.

What is Solar Position?

Solar position refers to the apparent location of the sun in the sky, typically described by two angles: azimuth and altitude.

Azimuth is the compass direction of the sun, measured in degrees clockwise from north (0° = north, 90° = east, 180° = south, 270° = west).

Altitude is the angle of the sun above the horizon, measured in degrees (0° = horizon, 90° = zenith).

Solar position changes throughout the day and varies with location, season, and time of year. This data is crucial for solar panel installation, solar energy optimization, and astronomical research.

How to Use This Calculator

Enter the latitude and longitude of your location in decimal degrees.
Select the date and time for which you want to calculate solar position.
Click "Calculate" to get the solar azimuth and altitude.
Review the results and chart showing the solar path throughout the day.

For accurate results, ensure your location coordinates are precise. Time zone is automatically calculated based on the entered date and time.

Formula Used

The calculator uses the following formulas to determine solar position:

Julian Day (JD)

JD = 367 × year - floor((7 × (year + floor((month + 9) / 12))) / 4) + floor(275 × month / 9) + day + 1721013.5 + (hour + minute / 60) / 24

Solar Mean Anomaly (M)

M = 0.9856 × (JD - 2451545) - 3.289

Equation of Time (E)

E = 9.29 × sin(M) + 0.14 × sin(2 × M) - 0.07 × sin(3 × M)

True Solar Time (TST)

TST = (hour × 60 + minute + 4 × (longitude - standardMeridian) + E) / 60

Hour Angle (H)

H = 15 × (TST - 12)

Solar Declination (δ)

δ = 23.45 × sin((360 / 365) × (JD - 81))

Solar Altitude (α)

α = asin(sin(latitude) × sin(δ) + cos(latitude) × cos(δ) × cos(H))

Solar Azimuth (A)

A = acos((sin(δ) × cos(latitude) - cos(δ) × sin(latitude) × cos(H)) / cos(α))

These calculations provide the solar position data used in the results.

Example Calculation

Let's calculate the solar position for New York City (latitude 40.7128°, longitude -74.0060°) on June 21, 2023 at 12:00 PM.

Julian Day (JD) = 2459747.0
Solar Mean Anomaly (M) = 90.5°
Equation of Time (E) = 0.5 minutes
True Solar Time (TST) = 12.008 hours
Hour Angle (H) = 0°
Solar Declination (δ) = 23.45°
Solar Altitude (α) = 73.5°
Solar Azimuth (A) = 180° (south)

At this time, the sun is directly overhead (altitude 73.5°) and positioned due south (azimuth 180°).

FAQ

What is the difference between solar time and clock time?: The calculator accounts for the Equation of Time, which adjusts clock time to solar time. This correction accounts for the Earth's elliptical orbit and axial tilt.
How accurate are the solar position calculations?: The formulas used provide accurate results within ±1° for most locations. For precise applications, consult specialized solar tracking equipment.
Can I use this calculator for any location on Earth?: Yes, the calculator works for any valid latitude and longitude coordinates. However, extreme locations may have limited solar data.
What is the solar path chart showing?: The chart displays the solar altitude and azimuth throughout the day, showing how the sun's position changes from sunrise to sunset.
How do I interpret the solar azimuth angle?: The azimuth angle indicates the compass direction of the sun. For example, 90° means the sun is in the east direction, while 270° means it's in the west.