’Astronomer Carl Wirtanen discovered his namesake comet in 1948. He was a skilled object hunter and used photos of the night sky to spot the quickly moving object, at least astronomically speaking.
Comet 46P/Wirtanen’s orbit keeps it pretty near to the sun. Its aphelion, or farthest point from the sun, is about 5.1 astronomical units (AU), which is just a tad bigger than Jupiter’s orbit. Its perihelion, or closest approach to the sun, is about 1 AU, just about the Earth’s distance from the sun. This path takes about 5.4 years to complete, meaning it comes back into view quite frequently compared to other famous comets.
Right now, it is approaching its perihelion. Its closest point to the sun will fall on Dec. 16 – which is why it will be brightest on this day.
Comet 46P/Wirtanen is a particularly active comet – called a hyperactive comet – and tends to be brighter than other comets of a similar size. This makes it a good candidate for viewing. Predictions suggest it will be as bright as a magnitude 3, which is a little brighter than the dimmest star in the Big Dipper, Megrez. However, there are some predictions that keep it beyond naked eye visibility at a brightest magnitude of only 7.6. The dimmest object visible with the naked human eye is magnitude 6, under perfect observing conditions.…’
Via The Conversation