TV & radio guide - Saturday

Theodore Roosevelt (8.55 am BBC2, also Sunday 8.10 am). Two-part documentary of US president.
Private Passions (12 noon R3). Robert Skidelsky, politic is academic (and Lord) chooses music.
Longitude (6.10 C4, also Sunday 7.00). Repeat of much praised version of Dava Sobel’s bestseller, first shown a year ago, with Michael Gambon as John Harrison.
Talking to Gotham (7.05 R3). Interval feature about George Plimpton.
The Secret Life of Japan: Snow in Japan (8.00 C4). Season on Japan begins with Jon Snow travelling from Osaka to Tokyo to ask about the current economic situation, talking to farmers, local politicians, the homeless and others … His interpreter, journalist Mayu Kamide, knows so much more than Snow that she could just as well have presented the programme herself. Also tonight: Teenage Japanese Killers (10.00 C4) and various late-night programmes featuring Japanese erotica etc.
» Castaway 2000 (10.00 BBC1). Live update from Taransay.
Great Exhibitions (4.10 am C4). Repeat of Jonathan Glancey’s excellent exhibition survey from last year, featuring 1851’s Great Exhibition in Hyde Park, the expositions in Paris (1889 and 1900) and those at Shepherd’s Bush (1908), Wembley (1924-5) and the South Bank (1951).