Queen spends day at the races as Diamond Jubilee celebrations begin

(CBS/AP) Queen Elizabeth II went to the races Saturday, at the start of a four-day celebration of her 60 years on the throne. It was a royal day as the queen watched a horse with the courtly name of Camelot win the Epsom Derby on Saturday.

Diamond Jubilee festivities officially began Saturday with a 41-gun salute fired by the King's Troop, Royal Horse Artillery at Horse Guards Parade in central London.

The 86-year-old monarch and her husband, Prince Philip, arrived at Epsom racecourse south of the capital for the Derby, one of the year's biggest horse-racing meetings. The queen waved to the 130,000-strong crowd as she was driven down the racecourse in a

Bentley bearing the Royal Standard - the car's sun roof kept shut under gray skies - before settling down to watch the races from the royal box.

The queen, wearing royal blue, was accompanied by members of the royal family including her sons Prince Andrew and Prince Edward and Andrew's daughters Princess Beatrice and Princess Eugenie.

The royals were treated to an aerial display by members of the British Army's Red Devils parachute team before the main event - the racing.

The monarch is a racing fan and horse breeder who reads the Racing Post each day over breakfast, although unlike many of her subjects she does not gamble.

"She's incredibly knowledgeable. Her knowledge of thoroughbreds and breeding goes way back," said Anthony Cane, chairman of Epsom Downs Racecourse.

Cane told the U.K.'s Daily Telegraph, "At the end of the day, her love is to come here. You have to remember, she comes here in a normal year in a private capacity not on an official visit. But she comes because she loves it, and this time it's her one trip to Surrey in the Diamond Jubilee."

The queen took the throne in 1952 on the death of her father, King George VI, and most Britons have known no other monarch.

Despite cool, damp weather in much of the country, hundreds of thousands of people are expected to participate in celebrations, including street parties, Sunday's 1,000-boat flotilla down the River Thames and a Monday pop concert in front of Buckingham Palace featuring Elton John and Paul McCartney.

Prime Minister David Cameron - the 12th British leader of the queen's reign - paid tribute to the monarch's "extraordinary level of physical energy, mental energy, and above all devotion to her people, to the institutions of this country, to the way our democracy works."

Not everyone in Britain will be celebrating. The anti-monarchist group Republic plans a riverbank protest as the flotilla goes by on Sunday, followed by a pub night where royal refuseniks can drown their sorrows.

The Diamond Jubilee weekend will feature the largest royal security operation ever, with about 13,000 officials including 6,000 police officers on duty.

An armada of vessels - from historic sailboats and barges to kayaks, lifeboats and military launches - was mustering along the Thames ahead of Sunday's river pageant. The queen aboard the royal barge will lead the flotilla of 1,000 boats - described by organizers as the biggest gathering on the river for 350 years.

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