Explore Scientific ED Air-Spaced Triplet APO Refracting Telescopes

Apochromatic (APO) lenses are designed to bring three wavelengths of light (red, green, and blue) into focus in the same plane. In contrast, achromatic lenses are corrected to bring two wavelengths into focus in the same plane.  Apochromats are also corrected for spherical aberration at two wavelengths, rather than one as in an achromat.

ED glass enhances apochromatic lens design by producing extra-low dispersion of the wavelengths of light passing through it thereby giving an even better apochromatic performance.  For more specifications and information on the different types of glass used in Explore Scientific apochromatic triplets, please click here.