Under the direction of Stephen Robert Kleiman, the New World Players Chamber Orchestra, in residence at the National Academy of Sciences, has appeared in a number of guises. Five of its members have performed as a chamber quintet. In the tradition of the Lincoln Center Ensembles and the Music From Marlboro players, it has formed groups to suit the requirements of the music, making possible a variety of programs. Kleiman's mission in all this is to bring to Washington audiences lesser-known works of well-known composers of the 18th, 19th and 20th centuries.

Saturday, the entire 35-piece orchestra was on hand for a concert that was a monument to Kleiman's programming philosophy and skill. It featured music by Honegger, Mozart, Chopin and Saint-Sae ns, all worthy if not exactly vintage pieces, which together provided a varied and well-structured program.

Honegger's "Pastorale d'Ete'," a bucolic evocation of birds and other natural summer phenomena, is charming if not profound. Mozart's Synfonia Concertante in E Flat, with a rather dubious provenance, is a square, predictable piece in which the oboe, clarinet, bassoon and French horn solos provide much of the music's grace. The "Krakowiak" Concerto Rondo, early Chopin and bumptious rather than elegant, is a sort of piano concerto movement. And Saint-Sae ns' Second Symphony probably deserves its obscurity although the final prestissimo movement is quite nice. The solos were handled well by members of the orchestra.

Kleiman's skills as a conductor do not match his skills as a programmer, however. His beat lacks grace, which in itself is no problem, except that it seemed to confuse his players at times. Cutoffs were ragged, and there were moments when the orchestra just didn't seem sure of itself. Person for person, this is an excellent group of musicians; they need only a clear and expressive beat to help them do their job.