This four-element 1.25" 2x Explore Scientific focal extender (Barlow lens) has an exceptionally flat field and essentially no color fringing with all telescope types and focal ratios.
The 1.25" 2x Explore Scientific premium Barlow (described by Explore Scientific as a focal extender, rather than a Barlow) 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 doubles the power of any 1.25"eyepieces used with it, providing high powers while maintaining thecomfortable eye relief of longer focal length eyepieces. This makes aBarlow/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 the 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.
While not specifically claimed to be apochromatic in performance, color fringing in this Explore Scientific focal extender is essentially eliminated with all telescope types and focal ratios.
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.
