ON AND OFF THE AIR:
* It's a musical evening of distinct contrasts tonight, beginning with the "Academy of Country Music Awards" from Nashville at 9 on NBC (Channel 2). It's the 26th annual broadcast, and that is a right long time to be honoring one of America's native music forms.
But a musical anniversary considerably longer in the tooth comes at 10 on Maryland Public Television: the "Tchaikovsky Birthday Gala" (channels 22 and 67). CBS' Charles Kuralt (whose own "CBS Sunday Morning" program is often the week's most artful show celebrating the arts), is the appropriate host.
The 90-minute gala was taped in December in the Great Hall in Leningrad, providing yet another example of TV's unprecedented recent penetration of the Soviet Union, like the TNT cable movie "Chernobyl: The Final Warning" reviewed here earlier this week.
The Tchaikovsky party includes performances by violinist Itzhak Perlman, cellist Yo-Yo Ma, singer Jessye Norman and pianist Boris Berezovsky performing with the Leningrad Philharmonic conducted by Yuir Temirkanov.
* A television viewers advocacy organization is mounting an assault on ABC in hopes of persuading the network to air seven unseen episodes of the Vietnam drama "China Beach."
"There is no reason not to air them," says Dorothy Swanson, president of Viewers for Quality Television, a national group based in Northern Virginia.
The award-winning series about nurses in the Vietnam War wrapped up production earlier this year, taping scenes in Washington in February for a final episode in which the characters have a 20-year reunion following the war.
But the series was lifted from the air by ABC, with that show and six preceding episodes not having aired. Fans have also complained about ABC's previous shift of the show from a Wednesday night air time to Saturdays, where it never found a big audience.
"Before these short-sighted, ill-advised programmers throw it away completely, please help VQT to challenge them to air the unseen episodes. It is time," writes Swanson in a mailing to critics. She urges viewers to write to ABC entertainment chief Robert Iger, at 2040 Avenue of the Stars, Century City, Calif. 90067.
Viewers can also write VQT at P.O. Box 195, Fairfax Station, Va. 22039 or call (703) 425-0075.
* Remember the news "leaks" earlier this year that said Johnny Carson was soon to be replaced on "The Tonight Show" permanently by substitute host Jay Leno?
Wrong! For late-night viewers, it is good news the network announced yesterday: Carson has signed for a 30th year, beginning in September. ("Tonight" is seen at 11:30 p.m., Channel 2.)