Actually it was discovered using a telescope. It just recently became visible to naked-eye observers.
"Backyard astronomers have been watching Machholz for months through telescopes. It was spotted by naked-eye observers for the first time about three weeks ago from the Southern Hemisphere, said Donald Machholz, who discovered the frozen chunk of rock and ice in August."
Machholz is probably using some sort of sky searching software looking for moving objects since he is the discoverer of 9 other comets. Not bad for a backyard amateur!
Ohhhhhhh! . . . Misread that one, didn't I? Thanks.
Here's his story...
Machholz Discovery