This sketch of comet Kohoutek was made on December 5, 1973, when the comet was magnitude 4.9 and had a tail 1.3 degrees long in a 5" refractor.
December 5, 1973. Gungin Gully, Western Australia. Naked eye limiting magnitude 5.0
Comet magnitude 4.9; Coma diameter 4.5 arc minutes; Tail length 1.3 degrees
5" f/5 refractor 16X 75X