With the usage of barlow lenses , you can extend the focal distance of telescopes and enhence the magnification of your observated deep sky objects. Thus, you can use the advantages of eyepieces with greater focal distance like the long eye relief as well as a more convenient insight at higher magnifications. Due to their 3-element air-spaced lens design with ED glass , these Barlow lenses provide a brilliant image quality for the whole visual field and are suitable for observations and photography.