Apochromatic Refractors, due to their unobstructed, text-book like diffraction patterns, produce the sharpest, highest quality optical imaging available, bar-none, aperture for aperture, of any telescope optical system.
The high-end Evostar-72ED Apo features a doublet objective lens, with one Extra-Low Dispersion (ED) glass element. Top quality Schott glass is utilised for the Crown element.
Each air-to-glass objective lens surface has exotic anti-reflection metallic coatings applied, to ensure optimum light throughput of approaching 99.5%!!
The proprietary Sky-Watcher “Metallic High-Transmission Coatings” (MHC) are the finest photon anti-rejection coatings in their class.
(Please note the Evostar-72ED Apo contains a different objective lens glass combination to the Evostar-80ED/100ED/120ED models)