Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Great Comet of 1861 formally designated C/1861 J1 and 1861 II, is a long-period comet that was visible to the naked eye for approximately 3 months. It was categorized as a Great Comet, one of eight in the 19th century. It was discovered by John Tebbutt of Windsor, New South Wales, Australia, on May 13, 1861, with an apparent magnitude of +4, a month before perihelion. It was not visible in the northern hemisphere until June 29, but it arrived before word of the comet's discovery.