Abbe sine condition

The Abbe sine condition is a principle in optical design that ensures a lens produces sharp, well-corrected images without distortion. It states that for a lens system to be free of certain aberrations, the sine of the angle at which light enters the lens must be proportional to the sine of the angle at which light exits the lens. In simpler terms, it helps align how light bends inside the lens so that images are clear and accurately reproduced across the entire field of view, especially in high-quality optical instruments like microscopes and telescopes.