WORTH NOTING ON TV

* TUESDAY

Frontline (PBS, 9-10 p.m., E.T.): In "Iran and the Bomb," Hodding Carter reveals that the heirs of Ayatollah Khomeini are engaged in a crash program that could give the Islamic republic nuclear weapons by the end of the decade - or maybe sooner. This spellbinding report reveals how Iran has concluded a deal with China for a research reactor that produces weapons-grade plutonium; spent millions of dollars to buy nuclear-related items across Europe; and sent a delegation last August to the former Soviet re public of Kazakhstan to buy uranium pellets and beryllium, a special metal component of nuclear bombs. As if the nuclear scenario were not enough, the report also alleges that Iran has a full-scale chemical- and biological-weapons program, in violation of international treaties.

General Motors' Playwrights' Theater (A&E, 9-10 p.m., E.T., repeated at 1 a.m., E.T.): Featured tonight is Canadian playwright Paddy Campbell's "The Parallax Garden," a one-act play about a lonely - or maybe not - divorced woman. Her yuppie son and daughter-in-law, who are separating to "consider their options," are afraid that mom, who is talking to her scarecrow over coffee, has gone over the edge mentally. Campbell's script asks the viewer to be the judge of what is real and what is not. Starring Jean

Stapleton, Judge Reinhold, and Beverly D'Angelo; directed by David Trainer. * WEDNESDAY

The National Geographic Specials (PBS, 8-9 p.m., E.T.): Wildlife photographers Des and Jen Bartlett have spent nine years camped along Namibia's Skeleton Coast in southwestern Africa watching the animals of the Namib Desert. The result is a spectacular film, "Survivors of the Skeleton Coast," featuring the first pictures of desert elephants, whose existence had before been in doubt. The film is an elegant plea for wildlife protection; it's worth watching just to see an elephant slide down a sand dune to a watering hole.

Please check local listings for all programs, especially those on PBS.