Glossary | Binoculars | Special features | ED
Lenses with special glass for high colour purity
ED Glass
Source: Celestron.com
Extra-low dispersion lenses deliver an excellent image that is virtually free from chromatic aberration, together with precise colour fidelity and enhanced resolution and contrast.
The illustration shows how ED glass combines the different colours of the object being observed at the focal point. Without ED glass, bright objects such as the Moon will have colour fringes. Birds’ colourful plumage appears dull and lifeless without ED glass.