Was a comedians famous catchphrase and here is what makes this popular science documentary so distinctively good. From the clear structure to the individual well-chosen contributors to the narrated script (uncredited), it was not just very lucid but engaging even compelling story-telling, the entire production done with artistry. The sense of awe, majesty and mystery which Patrick Moore's Sky at Night opening cleverly evoked, is the tone and standard yet does not compromise the solid science communicated throughout. It gives proper weight too to historic figures in astronomy using archive film clips. It is a demonstration and reminder of how science documentary-making can both be an art as well as science.I have to contrast this with the tendency to simply dispatch a (the?) popular TV scientist in a hire car to tour the USA, dropping in all over the place for a coffee and to listen with a camera crew over his shoulder.