Keychain: Zernike polynomial Z(8,4) Keychain

In 1933, Nobel Laureate Frits Zernike published a set of orthogonal polynomials designed to span the unit disc for the purpose of describing the aberrations of a circular mirror. Today these same polynomials are used to codify the imperfections in optical systems such as telescopes. Ophthalmologists and optometrists use them in wavefront guided vision correction. This magnet features the Zernike polynomial of order 8 and angular frequency 4, a complex valued function.