What is an ED eyepiece?
BBC Sky at Night Magazine's Scope Doctor Steve Richards solves your astronomy ailments.
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.
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