What is an ED eyepiece?

What is an ED eyepiece?

BBC Sky at Night Magazine's Scope Doctor Steve Richards solves your astronomy ailments.

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Steve Richards

What is an ED eyepiece?

Steve says: "Eyepieces contain several lens elements and these are designed using different types of glass to correct chromatic aberration: unwanted false colours, halos and colour fringing.

One type of glass that is particularly good at reducing chromatic aberration is known as ED glass.

ED stands for ‘Extra-low Dispersion’ and lens elements made from this type of glass reduce the distance between the plane of focus of the various wavelengths of light to produce a more saturated image.

Eyepieces with one or more ED lens elements produce more accurate colours, with less chromatic aberration than normal eyepieces."

Email Steve your astronomy queries to contactus@skyatnightmagazine.com and they could be answered in a future issue of BBC Sky at Night Magazine.

Author avatar

Steve Richards

Astronomer and author

Steve Richards is a DIY astronomy expert and author of Making Every Photon Count: A Beginner’s Guide to Deep Sky Astrophotography.
The three most common designs of eyepiece you’ll come across as an observer: an orthoscopic (left), a Plössl (middle) and a wide angle (right). Image Credit: The Secret Studio
The three most common designs of eyepiece you’ll come across as an observer: an orthoscopic (left), a Plössl (middle) and a wide angle (right). Image Credit: The Secret Studio

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