Comet 64P Wirtanen
On December 16th, Comet 64P Wirtanen will pass the Earth at 12 million kilometers away. It may become as bright as 3rd magnitude. The diffuse coma and a nearly full Moon will make observations difficult.
The associated image: Comet 46P's coma extends more than 45 arcminutes in this picture taken on November 26, 2018. Gerald Rhemann (Namibia) From Sky and Tel.
Two articles that explain the comet and how to observe it well are: