What was the most beautiful comet of the second half of the twentieth century, with two tails visible to the naked eye?
There was no such comet
Hale–Bopp was discovered on July 23, 1995 separately by Alan Hale and Thomas Bopp prior to it becoming naked-eye visible on Earth. Comet Hale-Boppit was visible to the naked eye for a record 18 months, twice as long as the previous record holder, the Great Comet of 1811. Accordingly, Hale–Bopp was dubbed the Great Comet of 1997.