Product Description Barlow lenses offer an easy, economical way to increase the magnification range of your eyepieces, and this Celestron Barlow is a high quality 2x version ideal for visual and some imaging applications. A Barlow lens doubles the magnifying power of your eyepiece by doubling its effective focal length. For example, an 18mm eyepiece used with a 2x Barlow lens would have the magnifying power of a 9mm eyepiece. If you’re looking for an affordable way to achieve high-power viewing of the moon and planets, double stars and even close up views of terrestrial subjects, a Barlow lens is the answer. Barlow lenses mount into either your telescope’s focuser or visual back. A Barlow lens is the astronomy accessory that keeps on giving! Insert it between your eyepiece and your telescope to get double the magnification instantly. Let’s say you have two eyepieces in your accessory case, a 10 mm and a 25 mm. Add a Celestron Omni 2X Barlow Lens to the mix, and now you have four magnifications to choose from. Combining this lens with the 25 mm provides double the magnification, or the equivalent of a 12.5 mm eyepiece, while the 10 mm gives you the power of a 5 mm eyepiece. Eye relief is the distance your eye has to be from the first lens in the eyepiece in order to see the full field of view. When you use a Barlow lens with an eyepiece, you get double the magnification, but the eye relief is not affected. This is a good thing, because normally the shorter the focal length of the eyepiece, the less eye relief you have. In other words, a standard 10mm eyepiece, as a general rule, will have better eye relief than a 5mm eyepiece. Bonus! The Celestron Omni 2x Barlow comes in a sleek, silver package. The two-element optics are fully multi-coated, and the edges of the lenses are blackened to cut down on internal reflections. The 1.25” barrel will fit in standard 1.25” focusers and diagonals, and the Barlow will accept 1.25” eyepieces. A metal thumbscrew locks the eyepiece firmly in place.
