For a thick lens made from spherical surfaces, the focal distance will differ for different rays, and this change is called spherical aberration.
22.
By expanding the internal field in terms of SVWFs and exploiting their orthogonality on spherical surfaces, one arrives at an expression for the T-Matrix.
23.
The " cylinder " and " axis " components specify how a particular lens is different from a lens composed of purely spherical surfaces.
24.
Data from the second CfA survey showed that galaxies were not evenly distributed but clustered on the spherical surfaces of empty " voids ".
25.
Since the spherometer is essentially a type of micrometer, it can be employed for purposes other than measuring the curvature of a spherical surface.
26.
Such conformal projections allow one to map pieces of spherical surface onto a plane while preserving the local angles of intersection, and hence zone symmetries.
27.
Additionally, the exploration of other surface types has been done to help bring surface computing to many other surface types, like curved and spherical surfaces.
28.
These can always be matched to a Schwarzschild vacuum across a spherical surface, so they can be used as "'interior solutions "'in a stellar model.
29.
However the approach is interesting, thinking of modern electronic camera sensors, which definitely cannot be forced into spherical surface shape, nor even manufactured as such.
30.
This is partly to do with the history of lens making but also because grinding and manufacturing of spherical surface lenses is relatively simple and cheap.
