I remember watching this as a kid and I fondly remember this as one of my favorite episodes, but I thought the rationalization by Willie that Chiron was one of the two planets that Alf speaks of was silly insofar as AFAIK Chiron was never considered a planet by scientists. The media of course spun it as such before a planet X sounds more provocative than reality, so I guess it is a neat way to rationalize Alf's claim of additional planets.
Considering the bad relations with Libya in the 80s I am surprised that the fictional mfg. of the TV came from Libya.