Tele Vue Barlows: "An Optically Perfect Window"
"A Little Nagler Goes Into Every Tele Vue Barlow"
Properly designed Barlows do wonderful things. First, they amplify power while retaining the eyepiece`s eye-relief. Second, they slow the telescope`s f/#, which improves eyepiece sharpness. Third, the designer can introduce compensations for eyepiece aberrations. Tele Vue`s 2" 2x BIG Barlow, 1 1/4" 2x and 3x Barlows were envisioned as magnification windows. Multi-coated high index glasses assure optimum aberration correction, exceptional contrast and virtually no light loss. Tele Vue Barlows achieve their design goals even when tested by the fastest scopes. They even improve our competitor`s eyepieces and telescopes!
For eyeglass wearers, the Big Barlow is perfect for doubling the power while retaining the eye-relief of 2" Tele Vue eyepieces such as the 55mm Plossl, 35mm and 27mm Panoptics (requires use of Panoptics Barlow Interface) and 20mm Nagler Type 2.
Our design approach includes mechanical conveniences. The Barlows are parfocal with our eyepieces and the BIG Barlow includes a parfocal 2" - 1 1/4" adapter. The BIG Barlow is threaded for 48mm filters and has a captive lock-screw. Both 1 1/4" Barlows are threaded for 1 1/4" filters.
Tele Vue Quality: Why compromise any optical link? Tele Vue product design and execution deliver consummate satisfaction. Every Tele Vue Barlow must pass the same rigorous f/4, full field testing as all our eyepieces before leaving our hands for yours.
User Report: "Tele Vue`s "Big Barlow" doubled the power but, like an optically perfect window, never gave any other indication that it was in the light path. The airy disc and surrounding diffraction rings were perfect, with no sign of astigmatism or coma. It will provide outstanding optical performance with all your eyepieces." -Alan Dyer Astronomy Magazine