Mirror lenses have split opinions for decades with most people falling either for or against, and the design is certainly not ideal for every genre of photography. Despite the contrasting market ...

However, most larger instruments – from backyard scopes for the more serious amateur to giant mountain-top tools to explore the universe – now adopt Newton’s method of curving mirrors (reflectors) ...

Other scientists had speculated that using mirrors rather than lenses might correct this problem, but Newton was the first to put such thoughts into practice. He cast a two-inch metal mirror and ...

Moreover, distortions created by the secondary mirror or imperfections in the primary mean they have drawbacks of their own, which these diffracting lenses may avoid. “If successful, these flat ...