Martin Haselboeck, organist of St. Augustin Church in Vienna, Austria, will play a recital at the Shrine of the Immaculate Conception at 8:30 p.m., Thursday. The program, which is free to the public, will include music by Mozart, Bach, Franz Schmidt, Schumann, Mendelessohn and the recitalist.

Maryland University's Music Department is bringing one of the country's leading sopranos and voice teachers, Phyllis Curtin, to its campus on Friday for a pair of master classes at 3 and 7:30 p.m. While those performing during the classes will be selected from the university, non-affiliated observers may attend. Tickets at the door of the Tawes Recital Hall.

Paul Callaway will conduct the Cathedral Choral Society's opening concert on Saturday at 4 p.m. in the Washington Cathedral. The all-Mozart program will offer the Litany in B Flat and the C Minor Mass. Soloists will be Regina McConnell, Nancy Williams, Charles Bressler and Robert Trehy. For ticket information, call 966-3423.

Speaking of tickets, it is a rare thing when tickets are available for any Philadelphia Orchestra concerts here. But there may still be a few subscriptions available for the orchestra's B Series, with conductors Ormandy, Muti and Tennstedt and soloists De Pasquale and Clifford Cutzon. For information, call 785-2670.

Gion Carlo Menott's Fable-opera, "The Unicorn, The Gorgon, and The Manticore," which had its world premiere in Washington at the Library of Congress, will be sung and danced again this week-end. On Saturday, at 8:30 p.m. and Sunday afternoon at 3, the work will be performed in the Kennedy Center Concert Hall by the Paul Hill Chorale and the Washington Ballet, a combine that filmed the unique composition some years ago for television. The program will also include "Carmina Burana" by Orff. In "Carmina." the accent is on the first syllable.

Things people may not know department: that pop star Jack Jones' father, tenor Allan Jones, long famous for his singing of the Donkey Serenade, sang some truly exquisite Bach in the St. Matthew Passion at St. Bartholomew's Church on New York's Park Avenue about 40-odd years ago when David McK. Williams was the organist and choirmaster there.

RCA Victor could make a valuable LP single of excerpts from the dozen 12-inch records on which Jones and an equally lovely soprano, Ruth Shaffner, sang in a way few Bach soloists today can equal. Jones fans would get a fine surprise. And since Williams was one of the country's great church musicians, such a disc would have real historical value.