Helios Sun Position Calculator Iphone

The Helios Sun Position Calculator helps you determine the sun's azimuth and altitude angles for any given location and time. This information is valuable for solar energy applications, astronomy, and outdoor activities.

What is Sun Position?

The sun's position in the sky is defined by two key angles: azimuth and altitude.

Azimuth - The compass direction of the sun, measured in degrees from north (0°) to east (90°), south (180°), and west (270°).
Altitude - The angle of the sun above the horizon, measured in degrees from 0° (on the horizon) to 90° (directly overhead).

Knowing these angles helps in optimizing solar panel placement, predicting daylight hours, and understanding seasonal variations in sunlight.

How to Use This Calculator

Enter your location coordinates (latitude and longitude)
Select the date and time for which you want to calculate the sun's position
Click "Calculate" to get the azimuth and altitude angles
View the results and chart visualization

For best accuracy, use precise location coordinates. The calculator uses standard astronomical algorithms to compute the sun's position.

Formula Used

The calculator uses the following formulas to determine the sun's position:

Solar Declination (δ)

δ = -23.45° × cos(360/365 × (n + 10))

Where n is the day of the year (1-365)

Hour Angle (H)

H = 15° × (local solar time - 12)

Solar Altitude (α)

α = arcsin[sin(φ) × sin(δ) + cos(φ) × cos(δ) × cos(H)]

Where φ is the latitude

Solar Azimuth (A)

A = arctan[(-cos(δ) × sin(H)) / (sin(φ) × cos(δ) × cos(H) - cos(φ) × sin(δ))]

The calculator also accounts for atmospheric refraction and solar time adjustments for accurate results.

Worked Example

Let's calculate the sun's position for New York City (40.7128° N, 74.0060° W) on June 21 at 12:00 PM (solar noon).

Day of year (n) = 172 (June 21)
Solar declination (δ) = -23.45° × cos(360/365 × (172 + 10)) ≈ -23.45° × 0.707 ≈ -16.57°
Hour angle (H) = 15° × (12 - 12) = 0°
Solar altitude (α) = arcsin[sin(40.7128°) × sin(-16.57°) + cos(40.7128°) × cos(-16.57°) × cos(0°)] ≈ 66.5°
Solar azimuth (A) = arctan[(-cos(-16.57°) × sin(0°)) / (sin(40.7128°) × cos(-16.57°) × cos(0°) - cos(40.7128°) × sin(-16.57°))] ≈ 180°

At solar noon on June 21 in New York City, the sun reaches its highest point in the sky with an altitude of approximately 66.5° and is directly south (azimuth of 180°).

Frequently Asked Questions

What is the difference between solar time and clock time?

Solar time is based on the sun's position in the sky, while clock time follows a standard time zone. The difference between them is called the equation of time, which varies throughout the year.

How does latitude affect the sun's position?

Higher latitudes experience more extreme seasonal variations in the sun's position. The sun's path is higher in the sky in summer and lower in winter, with the maximum altitude occurring at solar noon.

What is the solar declination?

Solar declination is the angle between the rays of the sun and the plane of the Earth's equator. It varies throughout the year, reaching a maximum of about 23.45° in summer and a minimum of about -23.45° in winter.