After being obscured for several days by moonlight, it was also found by Jean-Louis Pons on April 11, while Franz Xaver, Baron Von Zach was able to confirm Flaugergues' discovery the same night.

Based on these calculations, Heinrich Wilhelm Matthäus Olbers made a prediction that the comet would go on to become extremely bright later that year.

[8] By September, in Ursa Major, it was becoming a conspicuous object in the evening sky as it approached perihelion: William Herschel noted that a tail 25° long had developed by October 6.

Several astronomers continued to obtain telescopic observations for some months, the last being Vincent Wisniewski at Novocherkassk, who noted it as barely reaching an apparent magnitude of 11 by August 12.

[7] The Great Comet of 1811 was thought to have had an exceptionally large coma, perhaps reaching over 1 million miles across—fifty percent larger than the Sun.

It was the severest day of the great throes of the New Madrid earthquake; at the same time, a fiery comet was rushing athwart the horizon".

The artists John Linnell and William Blake both witnessed it, the latter producing several sketches and the latter possibly incorporating it in his famous panel The Ghost of a Flea.

[14] At the midpoint of War and Peace, Tolstoy describes the character of Pierre observing this "enormous and brilliant comet [...] which was said to portend all kinds of woes and the end of the world".