Zernike polynomials: the first 7 terms

Aberration
Type 
                  Seidel            Standard                             
Tilt (n=1,m=1) r cos(φ + φ0 ) 2r cos(φ + φ0 )
Defocus (n=2,m=0) r2  √3 (2r2 -1)
Coma (n=3,m=1) r3 cos(φ + φ1 ) √8 (3r3 -2r) cos(φ + φ1 )
Spherical aberration (n=4,m=0) r4  √5 (6r4 – 6r2 + 1)
Astigmatism (n=2,m=2) r2 cos(2φ + φ2 ) √6 r2 cos(2φ + φ)
Triangular Coma (n=3,m=3) r3 cos(3φ + φ3 ) √8 r3 cos(3φ + φ)
Quadratic Astigmatism(n=4,m=4) r4 cos(4φ + φ4 ) √10 r4 cos(4φ + φ4 )