Celestron SkyMaster 20 x 80 Binoculars When it's time to gaze at the stars or take in some long-distance or low-light terrain viewing, look no further than the Celestron 71018 SkyMaster 20 x 80 binoculars. Featuring high quality BAK-4 prisms, multi-coated optics for enhanced contrast, a diopter adjustment for fine focusing, and large apertures, these binoculars offer phenomenal performance. The Celestron 71018 features a 20x magnification and an objective lens diameter of 80 millimeters, giving it a 4-millimeter exit pupil.
(The exit pupil size - the diameter of the objective lens divided by the magnification - determines the amount of light available to your eye. The larger the exit pupil, the brighter the image obtained will be. A three-millimeter exit pupil is generally sufficient for daytime use, five-millimeters is suitable for daytime and twilight, and seven-millimeters is generally necessary for maximum nighttime or astronomy use.) The Celestron 71018 also includes an integrated tripod adapter rod, a deluxe padded soft carrying case.