Visible crew/equipment: When the crew leave the Red Dwarf game area, a boom mic is visible in the top right hand corner. (00:11:35)
Visible crew/equipment: When Holly says she is broadcasting on a higher frequency, when the crew are about to commit suicide, a boom mic can be seen in the top left of the screen. (00:23:30)
Visible crew/equipment: At The End of the episode, when Kryten explains why the Cat would kill himself, a boom mic shadow can be seen moving across his face,. (00:24:55)
Visible crew/equipment: At The End of the episode when Lister makes his speech, the first shot shows a close-up of his face, then it shows a wide shot. A boom mic is pulled out of shot at the top of the screen. (00:25:50)
Answer: The cello is a large four-stringed instrument, which, when it is played, stands vertically on the floor between the player's legs (assuming they are seated). If it is to grow as large as the other instuments mentioned will, it would require a rather unseemly lack of femininity to be able to encompass it with the legs.
Rooster of Doom