Ibn Sahl's law of refraction
Ley de la refracción de Ibn Sahl
- Date
- 984 · confidence high
- Place
- Baghdad, Iraq
- Credited to
- Abu Sa'd al-Ala ibn Sahl
- Field
- Communication
What was discovered
In his treatise on burning mirrors and lenses he states, in geometric form, a constant ratio equivalent to the sine law of refraction and uses it to design lenses that focus without aberration. He anticipates Snell and Descartes by more than six centuries.
Identified by Roshdi Rashed in 1990 while reconstructing the manuscript; it is a recent historiographical discovery. Ibn al-Haytham did not incorporate this law into his optics.
What it led to
- design of aspherical (hyperbolic) lenses
- optics of Ibn al-Haytham
- Snell-Descartes law