The American company Agema Optics designs first-class apochromatic refractors!
The exclusive optical design is based on a fluorite doublet with a special protective glass for the sensitive fluorite. Agema Optics has achieved excellent chromatic aberration correction with this lens. The result is a crisp image, essentially free of chromatic aberration that is unparalleled.
Agema Optics refractors are one-offs that are subject to very strict quality control before delivery.
The graph compares the Strehl number of different lenses. The Strehl number is a measure of the optical quality of telescopes. It states how close a lens comes to producing the ideal image. An ideal lens in the graph would achieve 100% at all wavelengths.
It can be seen that the lens on the Agema Optics Apo SD 130 far exceeds the values of classical refractors across all wavelengths of visible light and can compete with other top class apochromats.