This post introduces the Mathematics of Rayleigh Scattering, which is the optical phenomenon that causes the sky to appear blue. The equations derived in this tutorial will be translated into shader code in the next tutorial.

You can find all the post in this series here:

- Part 1. Volumetric Atmospheric Scattering
- Part 2. The Theory Behind Atmospheric Scattering
**Part 3. The Mathematics of Rayleigh Scattering**- Part 4. A Journey Through the Atmosphere
- Part 5. A Shader for the Atmospheric Sphere
- Part 6. Intersecting The Atmosphere
- Part 7. Atmospheric Scattering Shader
- Part 8. An Introduction to Mie Theory

You can refer to the Atmospheric Scattering Cheatsheet for a complete reference of all the equations used.

You can **download** the **Unity package** for this tutorial at the bottom of the page.