Tele Vue Nagler Planetary ZoomDescription Zoomable 50 Constant Apparent Field Eyepieces This is the "ultimate" tool for tweaking out the last bit of power that the atmosphere will permit. This model zooms from 6mm down to 3mm, and has click stops every mm. Al Nagler says of the Planetary Zoom, "I did not set out to design a zoom eyepiece, per se. David and I were discussing characteristics we'd like in a superior 'planetary' eyepiece, and the zoom feature answered one of the major