Antal Dorati is starting his Detroit career a little earlier than he had anticipated and with an exciting added opener. Thanks to a $325,000 grant from the Ford Motor Company, Dorati, the Detroit Symphony's new music director, is today beginning a series of nine programs for television. With "his" new orchestra, Dorati will film all nine Beethoven symphonies for programs that will be seen nationally on PBS in 1978.

Dorati had planned all along to open his first Detroit season with the Beethoven cycle, a series he just finished with "his" Royal Philharmonic in London. The Detroit films also will include some proceedings of the Beethoven Congress being held there between Nov. 4 and 6.

Speaking of Dorati, the Philharmonia Hungarica - with which he recorded the complete cycle of Haydn symphonies - will play a Kennedy Center concert on Friday, Nov. 4, at 8:30 p.m. Its new music director, Reinhard Peters, will conduct. Tickets are on sale at the Washington Performing Arts Society and the Kennedy Center.

Another just-announced concert will be given on Monday, Nov. 14, which is Aaron Copland's 77th birthday. In his honor, the National Symphony will play a Copland program, with the composer and Mstislav Rostropovich sharing the conducting assignments. Rostropovich recently said, "We planned this concert to coincide with his birthday as an especially happy welcome to the great composer."

Series openings: The Boston Symphony will play the first in its three-concert series here on Friday when Seiji Ozawa conducts the Brahms Requiem with Judith Blegen and Benjamin Luxon as soloists, together with the Tanglewood Festival Chorus. This series is a presentation of the Washington Performing Arts Society.

Eugene Ormandy and the Philadelphia Orchestra will open their Washington concerts on Monday, with Argentine pianist Martha Argerich as soloist in concertos by Haydn and Ravel. Ormandy will also conduct Washington's Birthday by Ives and the Mendelssohn "Scotch" Symphony.

The Lincoln Center Chamber Music Society's opening concert in the Kennedy Center on Oct. 29 will bring the local premiere of William Bolcom's Piano Quartet, a work commissioned for the society by the Koussevitzky Foundation in the Library of Congress.

The program will also include French horn soloist Barry Tuckwell in a Saint-Saens Romance, Mozart's Serenade No. 11 and the Dvorak Serenade for winds, cello and bass. Subscription tickets are still available at the Kennedy Center.

Replacement: Frederica von Stade, scheduled to sing the role of Nina in the Washington Opera's February production of "The Seagull" by Thomas Pasatieri, has temporarily withdrawn from public appearances while she gets ready for her first baby. Her place will be taken by Evelyn Petros who has sung the role in Houston and Seattle.

Sunday will be a busy day in music: The Washington Bach Consort, directed by Reilly Lewis, will inaugurate a series of free Bach concerts in Dahlgren Chapel of Georgetown University. At 5 p.m., they will present Cantata No. 100, the sixth Brandenburg concerto, and a flute sonata. Lewis plans to give all the Bach cantatas, at the rate of about one a month. That could take until around 1996, if he doesn't stop in the summer.

The King's Singers from London will sing the annual Founder's Day concert at the Library of Congress at 3 p.m. Sunday. And Sokol Opera of Washington will present Dvorak's opera, "The Stubborn Lovers," at 3 p.m. in Immaculate Auditorium at Tenley Circle. Tickets at the door.

That evening the Jewish Community Symphony plays its first concert of the season in the Center on Montrose Road, Rockville. The 8 p.m. concert is free.

The Colmcille Choir from County Derry in Northern Ireland will sing in St. Matthew's Cathedral at 8 p.m. Tuesday, Nov. 1. The concert will be a benefit for Ireland's Children, Inc., a non-profit organization set up to help Catholic and Protestant children escape the effects of the troubles in Northern Ireland.

The choir, begun in 1969, has won all the top prizes in Ireland, including the All-Ireland Ladies Choral Competition in Dublin. Tickets for the concert at the door. Information from 296-7660.