The all spherical surfaces are much easier to manufacture, especially in short focal ratios.

We specialize to the case of a spherical surface whose cross-section is shown in Fig. 3.5.

In the case of a two-dimensional spherical surface it would simply reproduce the sphere.

In terms of s the area of the spherical surface (at coordinate r) is.

For it vanished, utterly, along a geometrically perfect spherical surface.

A spherical surface like that of the Earth provides a simple example.

It will find a spherical surface, in other words, from which the distance of all the dots is a minimum.

"What my device lets you do is produce a smooth, spherical surface just the way nature intended," he said.

And what sense is there in a spherical surface that big?

Its mass pulls anything that touches it into smooth and reflective spherical surface.