Sun Position Calculator

Precise solar coordinates for any location on Earth.

Hourly Sun Position Data

Time	Elevation (°)	Azimuth (°)	Intensity (%)

What is a Sun Position Calculator?

A sun position calculator is a sophisticated tool used by researchers, engineers, and outdoor enthusiasts to determine the exact coordinates of the sun in the sky at any given moment. By providing specific geographic coordinates—latitude and longitude—along with the date and time, a sun position calculator outputs two primary angles: solar altitude (elevation) and solar azimuth.

Who should use a sun position calculator? Architects use it to design energy-efficient buildings with optimized natural lighting. Solar installers rely on it for solar panel efficiency calculator assessments. Even photographers use these calculations to predict the “Golden Hour.” A common misconception is that the sun is always directly overhead at noon; in reality, its peak height varies daily due to the Earth’s axial tilt, which is exactly why a sun position calculator is essential for precision.

Sun Position Calculator Formula and Mathematical Explanation

The math behind a sun position calculator involves spherical trigonometry and celestial mechanics. To find the sun’s location, we must first calculate the solar declination and the equation of time.

Step-by-Step Derivation

1. Day of the Year (N): Calculate the number of days since January 1st.
2. Solar Declination (δ): The angle between the rays of the sun and the plane of the Earth’s equator.
   
   δ = 23.45 * sin(360/365 * (N + 284))
3. Equation of Time (EoT): Accounts for the eccentricity of Earth’s orbit.
4. Solar Hour Angle (H): Converts local solar time into the number of degrees the sun has moved past the meridian.
5. Elevation (α): sin(α) = sin(δ)sin(φ) + cos(δ)cos(φ)cos(H)

Variable	Meaning	Unit	Typical Range
φ (Phi)	Observer Latitude	Degrees	-90° to 90°
δ (Delta)	Solar Declination	Degrees	-23.44° to 23.44°
H	Hour Angle	Degrees	-180° to 180°
EoT	Equation of Time	Minutes	-14 to +16 min

Practical Examples (Real-World Use Cases)

Example 1: Solar Panel Installation in Los Angeles

An installer uses the sun position calculator on June 21st (Summer Solstice) in LA (Lat: 34.05). The calculator shows a peak elevation of 79.4°. This data helps in best time for solar planning, ensuring panels are tilted to capture maximum irradiance during peak hours.

Example 2: Architectural Shadow Analysis

A designer planning a courtyard in London (Lat: 51.5) uses the sun position calculator for December 21st. The solar altitude at noon is only 15.1°. This low angle creates long shadows, requiring the use of a shadow length calculator to ensure the courtyard isn’t perpetually in the dark.

How to Use This Sun Position Calculator

Using our sun position calculator is straightforward:

1. Enter Coordinates: Input your Latitude and Longitude. You can find these using a latitude longitude lookup tool.
2. Set Date and Time: Use the pickers to select your specific moment of interest.
3. Adjust Timezone: Ensure the UTC offset matches your local clock settings.
4. Analyze Results: View the Elevation (height above horizon) and Azimuth (compass direction).
5. Review the Chart: The dynamic SVG chart shows the sun’s trajectory for the entire day, helping you identify sunrise sunset times.

Key Factors That Affect Sun Position Calculator Results

• Latitude: Your distance from the equator determines the maximum possible solar altitude.
• Seasonality: The Earth’s tilt causes the sun to appear higher in summer and lower in winter.
• Time of Day: Azimuth changes most rapidly near solar noon and sunrise/sunset.
• Atmospheric Refraction: Near the horizon, the atmosphere bends light, making the sun appear slightly higher than its geometric position.
• Longitude: Determines the exact timing of solar noon relative to your local clock.
• Earth’s Orbit: The elliptical shape of the orbit causes the “Equation of Time” variance, affecting solar angle guide accuracy.

Frequently Asked Questions (FAQ)

What is the difference between altitude and elevation?

In the context of a sun position calculator, they are synonymous. Both refer to the angular height of the sun above the horizon.

How is azimuth measured?

Azimuth is measured in degrees from North (0°) clockwise. East is 90°, South is 180°, and West is 270°.

Does this calculator account for Daylight Savings Time?

The sun position calculator uses the UTC offset you provide. If you are in DST, ensure your offset reflects that (e.g., -4 instead of -5 for EDT).

Why does the sun’s path change every day?

Due to the 23.5-degree tilt of the Earth’s axis and its orbit around the sun, the relative angle of the sun changes slightly every day.

Can I use this for solar panel orientation?

Yes, a sun position calculator is the primary tool for determining the optimal tilt and orientation (azimuth) for solar arrays.

What is “Solar Noon”?

Solar noon is the exact moment when the sun reaches its highest point in the sky for a specific location, crossing the local meridian.

Is the sun always in the South?

In the Northern Hemisphere, the sun is generally in the southern part of the sky at noon. In the Southern Hemisphere, it is in the North.

How accurate is this sun position calculator?

Our sun position calculator uses standard astronomical algorithms accurate to within 0.01 degrees, sufficient for most engineering and practical applications.

Related Tools and Internal Resources

• Solar Angle Guide – A comprehensive deep dive into solar geometry.
• Latitude Longitude Lookup – Find your exact coordinates for the calculator.
• Best Time for Solar – Learn how to maximize energy production.
• Shadow Length Calculator – Calculate shadow dimensions based on sun position.
• Sunrise Sunset Times – Get daily light duration data.
• Solar Panel Efficiency Calculator – Convert sun position into actual power output.