Observatory retired Observatory, who famously lowered the colours of Giant`s Causeway at Ascot last season, has been retired through injury, it was announced today.The John Gosden-trained son of Distant View sustained a hairline crack to his pelvis during the Prince Of Wales`s Stakes on his latest start, where he finished four and a half lengths behind Fantastic Light.His victory over Giant`s Causeway in the Queen Elizabeth II Stakes - ending a run of five successive Group One wins for Aidan O`Brien`s star - was one of the highlights of last year and came after his team hatched a plan to challenge late and wide of the teak-tough Irish runner.The four-year-old emerged victorious in six of his 10 career starts, with a second Group One prize coming in this season`s Prix d`Ispahan at Longchamp.He also numbered Group Three triumphs in the Jersey Stakes and Theo Fennell Lennox Stakes among his successes last term.'He is expected to make a full recovery and plans for his stud career will be announced shortly,' said Teddy Beckett, racing manager to owner Khalid Abdullah.