The Summer Opera Theater, which began life last year, gave the first of six performances of "The Merry Widow" by Franz Lehar last night in the Hartke Theater of Catholic University. The production will be repeated tomorrow, Sunday, Wednesday, and July 25, and 27.

Lehar's score is one of the world's gems, with a second act that is an unbroken string of glorious, seductive hit tunes. The Summer Opera Theater is offering a good-looking production with some attractive dancing and good choral singing on a stage that is well directed by John Lehmeyer.

Some of the time Lehar's music comes off well. At other times there are problems among the singers and in te orchestra pit. Conductor Benton Hess has trouble keeping the orchestra in tune and together with the singers. And when the music cries out for some real dalliance, as in the Rosillon-Valencienne duet, he plows ahead paying little attention to Lehar's ravishing phrases.

Myra Merritt in the title role, an assignment she will share with Deborah Lazenby, has the voice and style for the part. It is a pleasure to watch her and to enjoy her fine lyric soprano. She needs to indulge herself more in the soft top notes Lehar gives her, toying with them in the grandest manner. That's what they're there for. Let the conductor wait.

Stanley Gornett's Rosillon has the makings of a real triumph. He sings beautifully, with style and some elegance. He needs coaching in standing and movement. So do many in the cast. An exception to this was the really polished Njegus of Neil Smith. The others were acceptable in various ways without reaching any memorable heights. The pity is that many of them could with inspiring coaching.