WORTH NOTING ON TV

* FRIDAY

On the Issues (PBS, 10- 11 p.m.): Gather a group of figures prominent in a certain field. Pose a hypothetical situation. Then let a moderator guide the discussion, throwing in changes and complications as it progesses.

The result comes closer to real-life experience than most talking-head formats, and it has been known to put its panelists on the spot. Eventually they have to say where they stand.

This program used the technique last spring and with this show launches four new specials airing on consecutive Fridays. In the opener, ``Doing the Right Thing,'' business people and academics deal with the ethics of pleasing a client at a fictional ad agency. * SUNDAY

Booknotes 5th Anniversary special (C-Span, 8-10 p.m.): A look back at the history of the program.

Last Voyage of the Lusitania (TBS, 9-11 p.m.): A child's eager eyes peer out from an old photo on the TV screen. She is one of the many children booked on the 1915 voyage of the Lusitania from New York to Liverpool, England.

Cut to an interview with an elderly woman. She was the young girl and remembers vividly what happened when a torpedo from a German U-boat hit the the ship near the Irish coast. There was a small explosion, then a much bigger one. The ship sank with almost breathless speed - about 18 minutes - with the loss of 1,200 passengers. It was partly as a result of the attack that the United States entered World War I.

Juxtaposing the photos with survivor interviews and the use of other evocative production techniques make this documentary compelling, at times haunting, and at other times grisly and hard to watch. It follows Robert Ballard's inspection of the great ship - 300 feet below the surface - by means of submersible vehicles. What really sank the Lusitania? Did it bear a secret cargo of explosives bound for Britain, thus explaining the second explosion?

Dr. Ballard comes up with a new answer, which I won't give away. Martin Sheen narrates. Please check local listings for these programs.