A spherical surface is defined by only one parameter, the radius or curvature of the surface. If the surface is refractive, with different indices of refraction before and after the surface, then the ...

Ever wondered why Earth looks flat even though it's a sphere? The planet's massive size makes its curvature nearly impossible ...

Even from space, you wouldn’t detect something important about Earth’s shape: It’s not perfectly round. It’s actually a ...

Most trigonometry students look at triangles on a flat surface. However, people from ancient astronomers ... The Smithsonian collections are particularly rich in models for spherical trigonometry by ...

Ultraviolet - used within the 4 to 380 nm range. Other geometric lens specifications — such as radius of curvature, surface height, optical center, and lens thickness — are important to consider when ...