Kusiak on 26 December 2010 and both discoverers of Hale–Bopp used amateur equipment (although Hale was not an amateur). A number of periodic comets discovered...

closer than 1 AU to Earth — namely, the Great Comet of 1811 and Comet Hale-Bopp. At the time of the discovery of C/1881 K1, the Great Comet of 1881, its...