Solid Angle Calculator

Calculate the solid angle in steradians for a point source at a given distance

Input Parameters

Calculation Results

Calculation Formula

Ω = 4π(d² / (d² + (D/2)²))

Where:
Ω = Solid Angle (steradians)
d = Distance to Source (meters)
D = Source Diameter (meters)

Result

Solid Angle: 0.00 steradians

Solid Angle Calculator Usage Guide

Learn how to use the Solid Angle Calculator and understand the concept of solid angle

What is Solid Angle?

The solid angle is a measure of the amount of the field of view from some particular point that can be "seen" at a distance. It is the three-dimensional equivalent of the angle in two dimensions. The SI unit of solid angle is the steradian (sr).

How to Use This Calculator

  1. Enter the distance from the observer to the point source in meters.
  2. Enter the diameter of the source in meters.
  3. Click the "Calculate" button to compute the solid angle in steradians.
  4. The result will be displayed in the results section.

Applications of Solid Angle

Solid angles are used in various fields including astronomy (to measure the apparent size of celestial objects), physics (to calculate the intensity of light or other radiation), and engineering (to design lighting systems and sensors).

Example

If an observer is 10 meters away from a light source with a diameter of 0.5 meters, the solid angle subtended by the source as seen by the observer can be calculated using this calculator.