The world premiere of Daniel Pinkham's This Is the Day highlights the annual Summer School Chorus concert next Tuesday evening in Sanders Theater. The composer, harpsichordist with the Boston Symphony Orchestra, wrote the work for mixed chorus, brass and timpanl expressly for the Summer School Chorus.

Pre-Baroque and classical music are also included in the two-hour performance. Praetorius' "Canticum Trium Puerorum" for small and large choruses, brass enable, and organ; madrigals by Hassler killmayer, Marenzio, Monteverdi, and Morley; and three choruses from Handel's Solomon will be performed.

Harold C. Schmidt, professor of Music at Stanford University, will direct the Chorus. G. Wallace Woodworth, who conducted the Harvard Glee Club for 25 years and the Radcliffe Choral Society for 33 years, will return from Tanglewood as guest conductor for the Handel selections. Woodworth is known for his television series. "Two Centuries of the Symphony."

Haydn's Lord Nelson Mass, performed by the Summer School Chorus and Orchestra with soprano Jean Lunn, control to Betty Lou Austin, tenor Frank Modica, and bass Irving Pearson, will conclude the program.

Tuesday's concert will be televised on WGBH, Channel 2, and is open to the public without charge.

Organ Recital

Gustav Leonhardt noted Dutch organist, will present two concerts of 17th and 18th-century music at the Busch-Reisinger Museum next week. The concerts will start at 8:30 p.m. Wednesday and Thursday evenings.

Leonhardt, organist and harpsichordist at the Amsterdam Conservatory, has edited several studies of 17th century music. His book, The Art of the Fugue: Bach's Last Harpsichord Work, was recently published.

A limited seating capacity makes it necessary for people to obtain tickets in advance at the Summer School office, Weld 2. Both concerts are free.

Javanese gamelan music will be featured at a concert next Wednesday evening, starting in Paine Hall at 7:15 p.m. Mantle Hood, instructor in Music S-127, will provide commentary.