ENTERTAINMENT GOOD NIGHTWILL JOHN TESH'S SUCCESSFUL MUSIC CAREER EVER ECLIPSE HIS CELEBRITY AS THE GUY ON MARY HART'S LEFT?

During the previous day's interview, when the inevitable question of how long he will stay on ET in the face of all this recent musical success arose, Tesh curiously queried, "What do you think I should do?" Perhaps he already knows the answer or perhaps he isn't sure all that success will trail off without that constant TV exposure. After all, look what it did to Jackie Gleason, Steve Allen and David McCallum. Not to mention the Monkees! It's a tricky question to answer. If you were John Tesh, you'd probably be annoyed that this is yet another article that's working the TV angle. But Tesh has been a journalist long enough to know that if he didn't have such an interesting angle, people might not be writing about his music at all. John Tesh is scheduled to perform on Friday, June 16, at Symphony Hall. Showtime is 8 p.m.