The optical property of a system where chromatic aberration is corrected for three distinct wavelengths and spherical aberration is corrected for two. Achieving this requires carefully matching materials with different dispersion properties to eliminate the secondary spectrum that plagues simpler lens combinations.
The apochromatism of this new telescope design allows us to image the entire visible band without color halos.
Related terms
Apochromat
A highly corrected lens that brings three distinct wavelengths of light to the same focal point.
Apochromatic
Describes a lens or optical system corrected for chromatic aberration at three distinct wavelengths.
Achromatism
The condition of an optical system being free of chromatic aberration.
Spherical aberration
An optical defect where light rays passing through the edge of a lens focus at a different point than central rays.