This is a premium-quality wide field 2" eyepiece for the serious deep space explorer. Because of its long focal length, it is at its best with telescopes having a focal ratio of f/6 or longer. You can use the calculator below to see just how wide the field will be with your particular scope. For example, it will give you a 1.39 degree field at 49x with a big 17.5" f/4.5 Dobsonian. That's almost three lunar diameters and is ideal for observing large emission and reflection nebulas and nebula remnants. However, the 41mm Panoptic provides a huge 9.1mm exit pupil on an f/4.5 Dobsonian. This will actually waste some of the scope's light-gathering capacity, as it is unlikely that your eye can dilate wide enough to take in such a large exit pupil. Focal ratios of f/6 (a 6.8mm exit pupil) and longer will benefit the most from this very big and visually impressive eyepiece. So, while it's not particularly well suited for Dobsonian use, it can provide "picture window onto space" images with any other telescope type that can use a 2" eyepiece. The field of view is so wide that you actually have to move your head from side to side to take it all in. We measure the usable eye relief at a long 19mm, allowing the 41mm Panoptic to be used by eyeglass wearers with no vignetting of the field. The eyepiece is provided with a unique adjustable height eyeguard adapter that aids in properly positioning your eye in the exit pupil. This minimizes "pupil shadowing" and reduces stray light to maximize contrast. The soft rubber eyecup can be used fully extended or rolled back, whichever is more comfortable. You can also selectively extend one side of the eyecup to shield your eye from external light (such as a neighbor's porch light). The 2" TeleVue 41mm Panoptic would be a welcome addition to any serious eyepiece collection. Tech Details: Barrel Size 2" Eye Relief 19mm Field of view 68 Focal Length 41mm Number of optical elements 6 Weight 33.6 oz. Warranty Limited Lifetime
