Calculation of parameters and characteristics of telescopes using different eyepieces and visualization. Settings: - language (Russian, English, Hungarian, Spanish, German, French, Romanian, Croatian, Italian, Sinhala, Norwegian, Persian, Polish, Japanese, Portuguese, Korean, Catalan, Dutch, Arabic, Greek, Malay, Luxembourgish, Hindi, Indonesian , Ukrainian, Hebrew, Sardinian, Czech, Swedish, Finnish, Chinese, Bengali, Tamil, Slovenian, Turkish, Bosnian, Thai, Bulgarian, Vietnamese) - scale - text font size - input by the slider - comparison of telescopes - bookmarks - Moon phases - help - swipe Telescope: - List of telescopes - Diameter - Focal length - Focuser Eyepiece: - Eyepiece list - Focal length - Field of view - Barlow lens Camera: - list of cameras - pixel size - image size - matrix size - Binning Calculations: - Magnification - Stellar magnitude - Field of view - Maximum field of view - f-number - Diameter of exit pupil - Angular resolution - Size of craters on Moon - 2D, 1.4D, 1D, 0.7D, 0.5D - Sun - ISS Planets: - Mercury - Venus - Earth - Mars - Jupiter - Saturn - Uranus - Neptune - Pluto Asteroids: - Ceres - Pallas - Juno - Vesta - Ida - Gaspra Satellite: - Moon - Titan - Io - Europa - Ganymede - Callisto - Titania - Ray Messier: M1, M8, M13, M16, M17, M20, M27, M31, M33, M42, M45, M51, M57, M58, M63, M64, M74, M78, M81, M82, M83, M88, M97, M99, M100, M101, M104, M108 NGC: 891, 2359, 2392, 2440, 4565, 4631, 5189, 6302, 6543, 6960, 6979, 7000, 7662 IC: 1805, 1848, 2118