With a large 102mm objective lens, the Celestron Star Sense Explorer DX 102 App-Enabled Refractor Telescope is able to produce exquisite detail & clarity when viewing celestial objects. This is made even better by Celestron's XLT optical coatings which in turn improve light transmission, enhancing the image you will see. Using your phone as your guide to the stars, Celestrons Star Sense sky recognition technology will analyse the stars above you & calculate your position in real time. Once your position is obtained, the app will automatically generate a list of objects currently visible. A manual altazimuth mount also allows for smooth, dual-axis slow-motion control; making it easy to follow the directions that appear on the Sky Sense Explorer App.