Orion E-Series 7-21mm Zoom Eyepiece

Now even casual telescope users can enjoy the benefits of zoom eyepiece technology. A simple twist of the barrel of the affordable E-Series Zoom eyepiece changes the focal length from 21mm to 7mm, or to any focal length in between. That makes it ideal for locating an object at low magnification, then quickly zooming in to higher magnification for closer inspection, all without changing eyepieces! Actual magnification range will depend on the focal length of your telescope, but as an example: in an Orion SkyQuest 8" Dobsonian reflector with a 1200mm focal length, this eyepiece provides a continuous magnification range of 57x-171x. And the E-Series Zoom works equally well for astronomical or terrestrial viewing in smaller refractor or Cassegrain design telescopes. This 6 element telescope eyepiece boasts fully multi-coated optics and exceptionally long eye relief ranging from 18mm (at 21mm) to 16.3mm (at 7mm). The apparent field of view angle ranges from 40-deg (at 21mm) to 57-deg (at 7mm). The 1.25" barrel is threaded for standard eyepiece filters. A very nice value in a quality zoom eyepiece!