Concertmaster Norman Carol said Mr. Panitz, who recently had announced he would retire next spring, was "one of the great flutists and part of the tradition of great flute playing that this orchestra has. He considered the orchestra as part of his family."
Born in New York City, Mr. Panitz began studying the flute at 12, a relatively late start. He graduated from New York's High School of Music and Art at 15, but had to enroll for an extra year because although the Eastman School had accepted him it had a rule against students younger than 16.
In high school he met Myrna Rubenstein, a pianist who later entered the Eastman School with him. Mr. Panitz studied four years with Joseph Mariano, and Rubenstein accompanied Mariano's students. They were married in September 1945.
Mr. Panitz earned a master's degree at the Manhattan School and joined the National Symphony briefly before being drafted. He played in the Army Air Corps Band in Washington.
He joked with friends that he and the band director clashed from the beginning. Mr. Panitz said the conductor told him he "wouldn't have him play first flute in his band even if he were first in the Philadelphia Orchestra."
After his military service, Mr. Panitz returned to New York, where he established himself as a free-lance flutist and was much in demand. He performed with the Bell Telephone Orchestra and was principal flutist with the New York City Ballet, the Symphony of the Air and the Little Orchestra Society of New York.
When he joined the Philadelphia Orchestra, he followed the legendary flutist William Kincaid, but his artistry was so immediately apparent that he suffered none of the damaging comparisons that often follow such a highly visible change.
He became a favorite among his colleagues, noted for his softly spoken quips that eased tensions in rehearsals, as well as for his high standards.
Principal bassoonist Bernard Garfield, who went to high school with Mr. Panitz and who drove him to the hospital on Monday, said that "Murray was always a compassionate listener, honest and trustworthy. In the orchestra, he was so aware of intonation that he could modify his playing to correct a pitch problem even before (others realized) there was a problem.
"His technique was remarkable, and his ability to read new music always made it seem as if he had known the music already," Garfield said.
Mr. Panitz appeared as soloist with the orchestra on many occasions. Eugene Ormandy, the late conductor of the Philadelphia Orchestra, featured him on tours by playing Kent Kennan's Night Soliloquy as an encore, a piece for flute and orchestra.
He last appeared as soloist with the orchestra at the Mann Music Center in July, playing a Cimarosa Concerto for Two Flutes with James Galway.
He also had been a member of the Philadelphia Woodwind Quintet, again succeeding Kincaid in the ensemble. Anthony Gigliotti, a founder of the quintet and the orchestra's principal clarinetist, said, "What an asset he was to the group! He had a prodigious technique, beautiful sound and perfect ear."
Gigliotti praised the flutist's open mind. He recalled that Mr. Panitz had never liked gold flutes until, when the orchestra was playing in Ann Arbor, Mich., he heard one that was outstanding. "He bought it and switched immediately," Gigliotti recalled. "He had played that instrument ever since."
Mr. Panitz had taught at Curtis Institute and more recently at Temple University. Since 1974, he had sat in the orchestra beside flutist Loren Lind, who had studied with him for four years. "He was demanding, but in a very positive way. He made you want to know everything," Lind said.
In addition to his wife, Mr. Panitz is survived by his daughter, Amy Jo Fuge, and two grandsons.
Funeral services will be private. A memorial service will be held at noon April 23 in the Academy of Music ballroom. Plans are being made for a scholarship fund in Mr. Panitz's memory.