For high power with a short focal length refractor or reflector, this Explore Scientific four-element 5x image amplifier (Barlow lens) is hard to beat. It quintuples the power of any eyepiece used with it, with a flat field and essentially no color fringing .
This very high power four-element 1.25" 5x Explore Scientific premium focal extender (Barlow lens) uses an advanced four-element optical design to deliver a flatter field-of-view with sharper field edges than even the best three-element apochromatic Barlows.
This Explore Scientific focal extender multiplies the power of any 1.25" eyepiece used with it by five times, providing very high powers while maintaining the comfortable eye relief of longer focal length eyepieces. This makes a Barlow/long focal length eyepiece combination ideal for those who must wear eyeglasses while observing due to astigmatism.
All air-to-glass surfaces are fully coated with multiple layers of individually tuned ion-deposited anti-reflection materials for maximum light transmission and contrast. The lens edges and all internal metal surfaces are blackened to maximize image contrast. Your eyepieces are held in place by a non-marring clamp ring that won't scratch your eyepieces as a conventional metal thumbscrew can.
Its very high power 5x optical system is a perfect match for short focal length refractors or reflectors - particularly for viewing or imaging planets in minute detail. While it is not specifically claimed to be apochromatic in performance, color fringing in this Explore Scientific focal extender is essentially eliminated, regardless of the telescope type and/or focal ratio.
This Explore Scientific focal extender is protected by a one year warranty that can be extended to a transferable limited product lifetime warranty at no cost by simply sending in the warranty card. With the extended product lifetime warranty, this Explore Scientific focal extender is protected for as long as it continues to be manufactured, plus an additional five years.
