The musicians from Aston Magna specialize in the performance of 17th and 18th-century music and dance, playing on old instruments with extraordinary insight into performance practices of those days.

Last night in the Smithsonian's Hall of Musical Instruments, led by the enlivening musical knowledge and playing of Harpsichordist Albert Fuller, these musicians presented Sammartini, Mozart, Telemann and Haydn, and, at the end, offered a Clerambault cantata in which they were joined by soprano Carole Bogard.

Nothing in the entire program revealed more of the achievement of Aston Magna than the style and mood of the cantata, on the subject of Medea and Jason. It was instantly clear that this was not shattering tragedy, a la Cherubini. Rather, as Fuller suggested at the beginning of the evening, it was the kind of music that sought to introduce the Italian manner of opera into after-dinner Parisian salons.

It was one of the styles of music that split "tout Paris" into warring factions in the war of the buffoons that exploded in the years immediately after Clerambault's death. All this was hinted at as Bogard moved from direct narration through arias in varying emotions, never becoming too seriously involved in any of them. It was a kind of ideal performance.

So, too, in their ways, were the per formances of gambist John Hsu; Bernard Krainis, recorder; Fortunato Arico, the superb cellist; David Miller on viola; Linda Quan, violin; and Thomas Wolf on the violone. Frequently undergirding and brilliantly ornamenting at appropriate times was Fuller's playing of the Smithsonian's Dulcken harpsichord.