text: Placidus Fixlmillner calculated the orbit of this object based on data collected by John Flamsteed and Tobias Mayer.
full_question: Placidus Fixlmillner calculated the orbit of this object based on data collected by John Flamsteed and Tobias Mayer. Anders Lexell computed the orbit of this entity and mathematically proved it was not a comet. Because of its limb darkening, the radius of this object was not correctly calculated until its 1977 stellar occultation. Like the asteroid Ceres, the existence of this planet was predicted by the empirical Titius-Bode law. A sea of water and ammonia gives rise to its magnetic field, which is unusual for not originating from its interior. William Herschel discovered this planet, whose moons include Titania and Umbriel. For 10 points, name this tilted gas giant between Neptune and Saturn.
first_sentence: Placidus Fixlmillner calculated the orbit of this object based on data collected by John Flamsteed and Tobias Mayer.
raw_answer: Uranus