Filled with knots and eddies of dusty plasma, Lovejoy's tails stretches more than 20 degrees across the sky--long enough to overlap 40 full Moons or fill the Bowl of the Big Dipper twice.
At closest approach to the sun or "perihelion" on Dec. 23rd, the comet will be just inside the orbit of Earth (0.82 AU). The extra heating it gets at perihelion will grow the tail even more.
Comet Lovejoy shines like a 4th magnitude star so it is barely visible to the unaided eye (especialy when the sky is filled with full moonlight). However, for backyard telescopes, the comet is a fairly easy target rising ahead of the sun in the eastern morning sky.
If you have a GOTO telescope, send it to these coordinates. Slight pointing errors are no problem, because the tail is almost too broad to miss.
Sky maps: Dec. 18, 19, 20.