Sun Position Calculator App

Understanding the sun's position in the sky is essential for solar energy applications, agriculture, and navigation. Our sun position calculator app provides accurate azimuth, altitude, and solar time calculations for any location and date.

What is Sun Position?

The sun's position in the sky is defined by two main parameters: azimuth and altitude. These measurements help determine the sun's direction and height above the horizon, which is crucial for various applications including solar panel installation, agricultural planning, and navigation.

Key Terms

Azimuth: The angle between the sun's position and true north, measured clockwise from 0° to 360°.
Altitude: The angle between the sun's position and the horizon, ranging from 0° (sunrise/sunset) to 90° (solar noon).
Solar Time: The time based on the sun's position rather than the clock time, accounting for the equation of time.

Accurate sun position calculations require considering factors such as the observer's location, date, time, and local time zone. Our calculator app uses advanced algorithms to provide precise results for any given parameters.

How to Use This Calculator

Using our sun position calculator is straightforward. Follow these steps to get accurate results:

Enter your location coordinates (latitude and longitude).
Select the date and time for which you want to calculate the sun's position.
Choose your local time zone to ensure accurate solar time calculations.
Click the "Calculate" button to generate the results.
Review the azimuth, altitude, and solar time values displayed in the results section.
Optionally, view the sun path chart to visualize the sun's movement throughout the day.

Input Requirements

Latitude: -90° to 90° (positive for northern hemisphere, negative for southern).
Longitude: -180° to 180° (positive for eastern hemisphere, negative for western).
Date: Any valid calendar date.
Time: 24-hour format (00:00 to 23:59).

Formula Used

The sun position calculations are based on the following formulas:

Solar Position Algorithm

The algorithm calculates the sun's position using the following steps:

Calculate the day of the year (n) from the date.
Compute the solar declination (δ) using the formula:
δ = 23.45° × sin(360° × (284 + n)/365)
Determine the equation of time (EOT) to adjust for the sun's apparent motion.
Calculate the hour angle (H) based on the local solar time.
Compute the solar zenith angle (θ) using:
θ = arccos(sin(φ) × sin(δ) + cos(φ) × cos(δ) × cos(H))
where φ is the observer's latitude.
Derive the solar altitude (α) from the zenith angle:
α = 90° - θ
Calculate the solar azimuth (A) using:
A = arctan2(sin(H), cos(H) × sin(φ) - tan(δ) × cos(φ))

These formulas account for the Earth's axial tilt, orbital eccentricity, and the observer's location to provide accurate sun position calculations.

Example Calculation

Let's calculate the sun's position for New York City (40.7128° N, 74.0060° W) on June 21, 2023 at 12:00 PM (noon).

Example Inputs

Latitude: 40.7128° N
Longitude: 74.0060° W
Date: June 21, 2023
Time: 12:00 PM
Time Zone: Eastern Time (UTC-4)

Using the calculator with these inputs, we get the following results:

Example Results

Azimuth: 180.00°

The sun is directly south at solar noon.

Altitude: 73.53°

The sun is at its highest point in the sky for the day.

Solar Time: 12:00:00

The solar time matches the clock time at solar noon.

This example demonstrates how the sun's position changes throughout the day and how our calculator can help you understand these variations.

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 standardized time zone. The equation of time accounts for the difference between these two times, which can be up to 16 minutes on certain dates.

How does latitude affect the sun's position?

Latitude determines the maximum altitude the sun can reach in the sky. Locations closer to the equator experience higher maximum altitudes, while locations closer to the poles have lower maximum altitudes.

Can I use this calculator for any date and time?

Yes, our calculator can calculate the sun's position for any valid date and time within the supported range. Simply enter your desired date and time to get accurate results.

What is the solar declination?

The solar declination is the angle between the rays of the sun and the plane of the Earth's equator. It varies throughout the year due to the Earth's axial tilt and orbital motion.

How accurate are the calculations?

Our calculator uses precise algorithms and astronomical data to provide accurate sun position calculations. The results are typically within a few tenths of a degree of the actual sun position.