Turn to the middle of the programme for the Auckland Philharmonia's Spring Season concerts and you'll find a breathtaking centrefold showing the Town Hall filled from stalls to balcony.

The photograph has been taken from behind the orchestra. Cellist Jeremy Turner is taking a bow and the audience is clapping enthusiastically. It's a shot that recalls a similar iconic image of the audience at the 1906 International Exhibition in Christchurch.

Auckland's own orchestral icon, the Philharmonia, is celebrating its silver jubilee on Friday night.

It's hard to believe that a quarter-century has passed since the Auckland Regional Orchestra, as it was then called, was launched with a sellout concert in the same building.

The conductor, Georg Tintner, introduced Beethoven's Second Symphony at length, pointing out how this chamber orchestra had no qualms about tackling Beethoven.

There was simply no saying "no" to musicians determined to establish a secure and professional orchestra in their city and region. A timeline in the programme booklet for this year shows a community that cherishes its orchestra - audiences zoomed from 25,200 in 1981 to 492,800 this year.

The succession of general managers have included the debonair Michael Maxwell, and Christopher Blake, who established a special relationship between the orchestra and the New Zealand composer.

On the conducting side, after the initial fatherly support of John Hopkins, characters such as Erich Bergel and Enrique Diemecke made their marks.

Miguel Harth-Bedoya gave us Golijov and glamour, and his sleek good looks underpinned the AP's shrewd marketing ploys of the late 90s.

On Friday night that charismatic conductor will be remembered in two Latin American works, by Galindo and Revueltas, plus some numbers the orchestra has always considered its favourites.

There is a star violinist in Eugene Fodor, who has opted for two shorter offerings (Ravel's Tzigane and Chausson's Poeme) rather than a weighty concerto. And anyone who went to last Friday's concert will welcome the chance to experience conductor Mischa Santora once again.

A few months back, when we were discussing his upcoming symphony, composer Ross Harris chuckled over his final AP commission for the year.

Cento, which is on Friday night's bill, is a patchwork of the different music that the orchestra has played, from two rousing marches and symphonic musings to a song by Goldenhorse. The pieces are named in the programme and the audience can test their recognition abilities by scoring themselves out of 22. Less than eight, and the orchestra advises that "we really think you ought to come to a lot more of our concerts so you can pick tunes instantly".

The AP has had more than its share of woes this year, and with appointments still to be decided for general manager, music director and concertmaster, artistic administrator Antony Ernst is a busy man.

Ernst, an Australian, staggered many when, within 24 hours, he organised American violinist Mark Kaplan to deputise for an ailing Salvatore Accardo in June. "My first day of work turned into my first night of work." He can laugh now, but for a while it must have been baptism by terror.

Five months on, he is proud to be associated with players who "never lose sight of the fact that it's about the music. There's none of that jaded thing that you get with even the biggest orchestras. They are a very generous-spirited and committed bunch."

With an impressive background in opera and with the Sydney Symphony, Ernst sees the orchestra's 25th as "a milestone for an orchestra going through a lot of changes and coming through ready to celebrate the beginning of something new". The celebrations begin on Friday. Don't miss them.

When: Friday, 8pm