Apparent Angular Diameter

How to use this tool

1. Calculate the angle subtended by a circular object of known diameter and distance.
2. Set object diameter, distance in the indicated units.
3. Calculate and compare angular diameter, angular diameter.

Try this example

{
  "d": 1,
  "r": 100
}

Accuracy and scope

Idealized educational model. Enter measured values in the displayed units; real systems may require additional corrections.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.