CONDUCTOR James Holmes has urged Sinfonia Viva's musicians to each bring one vital piece of equipment to Sunday's annual Darley Park concert – a clothes peg.

"It's the wind," he says. "That's our chief enemy. We always have to bring a large supply of clothes pegs, as there's nothing better for keeping sheets of music on the stand.

"The conductor has to turn over a score so fast, I can't really do that – I'd be all fingers and thumbs. So it's clothes pegs for the orchestra, and they try and build a bit of a windbreak for me, down the edge of the stand.

"And if that doesn't work we all just hope we know the music well enough. Viva is a great orchestra; they are very experienced, adaptable and quick to work things out.

"We always worry about the sudden gust of wind... the onset of a thunderstorm. It goes with the territory, but we all go out there to make the music great and to have a bit of fun with it, and communicate with the people watching."

James has become a regular at what is Britain's largest free outdoor classical concert, and loves the Derby atmosphere.

"It's a great event and I think it's wonderful that it encourages so many people to roll up," he says.

"And it is about the biggest event in the city, apart from a match at the Rams.

"Obviously we hope the weather will be kind to us. I have done five or six of these, and it's been mixed.

"But we keep our fingers crossed and whatever the weather it's a great atmosphere, especially in the second half, when it goes dark and all the lights come on."

The Darley Park concert has now been incorporated into the Feste arts weekend and will be the closing concert of three days of outdoor activities that will attract as many as 50,000 people.

"I'm delighted about that," says James. "Anything that involves people in the arts on a big scale is to be welcomed and Derby is taking an active role in doing that. It can only be good for the city."

This year is the International Year of Astronomy, and the concert is taking on an appropriate space theme.

"In serendipitous fashion it's the 40th anniversary of the Apollo XI moon landing and the 400th anniversary of Galileo's use of the telescope," says James. "So it's a big year for people who watch the sky. And the stars, the planets and the moon have always inspired artists, writers, thinkers and, of course, musicians. It's a good thing to home in on.

There will be pieces from Strauss, Mozart, Hayman, Sousa, Williams, Dvorak and Mancini, and Sinfonia Viva will also treat audiences to astronomically-linked music from 2001 Space Odyssey, The Magic Flute, ET and Star Wars.

But having even a strong theme doesn't always make programming easier for these concerts, as James explains.

"It might have seemed obvious to do something from The Planets, but that needs a larger orchestra, and if you scale down, the pieces fail to have impact.

"Fundamentally, this is a concert about the best music-making we can come up with, but it also has to be fun, on this kind of evening.

"That tends to mean that we connect with the theme rather tenuously at times. For example we are doing an orchestral version of Bohemian Rhapsody, and the only connection there is Freddie Mercury... and Galileo is mentioned in the lyrics.

"But other pieces are more directly related, like the aria Song to the Moon.

"This year John Williams feature heavily as we couldn't ignore him with Star Wars and ET looking at what life may be out there in space."

James is looking forward to meeting Derby County's official tenor Thomas Spencer Wortley who will be bringing his football ground singing skills to the concert.

"You have to admire anyone who goes out there in front of a big sports crowd," says James. "He doesn't even have a symphony orchestra giving him a nice cushion underneath. It's a frightening thing. But I'm sure after doing that he should find Darley Park pretty amenable."

The concert will end with the traditional fireworks finale - coordinated to the music.

"The fireworks guys know what music we are going to do and I try to answer their questions about the speed of a particular passage. Then they plot where they want certain effects. It can't be an exact science but every time I have done it I'm astounded at how accurate they get it.

"I don't know how they do it, It's an art in itself. To orchestrate something like that is every bit as creative as me conducting the piece."

SINFONIA VIVA

WHERE: Darley Park.

WHEN: Sunday, September 6 (from 5.30pm).

ADMISSION: Free, parking £5 per car.

In the interest of safety do not bring barbecues, sparklers, animals, tents or gazebos to the park. Do bring a torch.