Uranus is barely visible to the naked eye at magnitude 5.7 and appears as a tiny blue-green disk of 3.5-4 arcsec in telescopes, with the color coming from methane absorption in its hydrogen-helium atmosphere. A 200mm or larger telescope can distinguish it from a star; it won't twinkle and shows a distinctly non-stellar disk at high power. William Herschel discovered Uranus on March 13, 1781, the first planet found with a telescope. He initially reported it as a comet. The name comes from the Greek god of the sky, father of Kronos (Saturn). Uranus is unique for its extreme axial tilt of 98 degrees — it essentially rolls around the Sun on its side, likely from a giant impact early in solar system history. This creates extreme seasons where each pole gets 42 years of continuous sunlight followed by 42 years of darkness. Voyager 2 made the only flyby in January 1986, revealing 10 new moons, two new rings, and a surprisingly bland atmosphere (though later HST observations show seasonal brightening). Uranus has 13 known rings (narrow and dark) and 28 known moons, with the five largest — Miranda, Ariel, Umbriel, Titania, and Oberon — discovered from Earth. Oberon and Titania are visible in large amateur scopes.