Explore Scientific 3x Tele Extender, 2" - 4 elements, telecentric

Explore Scientific 3x Focal Extender & 2" Barlow Lens

With focal extenders (also teleextenders) you extend the telescope focal length and thus increase the magnification for the observation of moon, planets or small deep-sky objects. This allows you to benefit from the advantages of longer focal length eyepieces, such as the large interpupillary distance and a more pleasant view at higher magnifications.

These highly corrected focal length extenders offer outstanding image quality in the entire field of view thanks to their four-lens design and are therefore ideal for visual observation and photography. The combination of the best anti-reflective coating and telecentric design makes the focus extender clearly superior to ordinary Barlow lenses.

The advantages of a telecentric Barlow lens

In addition to the advantages of a typical Barlow lens, the telecentric design has two other advantages: First of all, the magnification factor is independent of the eyepiece distance, so you can put double polarizing filters, filter drawers and similar accessories between the lens and the eyepiece without increasing the magnification factor.

And second, the telecentric design does not extend the eye relief of the connected eyepiece. This is advantageous for the long focal length eyepieces that are often used in this context with their usually already large eye relief, as if this is too big, one can hardly hold the viewing position, which possibly leads to kidney being.