The Osaka hotel barman, who was not a homosexual, went there at 2am to take photographs when the 20-year-old, accompanied by a 15-year-old youth, attacked him.
The court heard the 20 year-old had gone to Calton Hill because it was known as a meeting place for homosexuals, whom he saw as easy targets to attack and rob.
He was making his way home when he was confronted by his attackers in Royal Terrace.
They compelled him to go up Calton Hill nearby, where the sexual assault took place.
Detectives investigating the sex attack on a 32-year-old homosexual at Calton Hill, which is also a popular sightseeing spot, say at least two assailants were involved.
The victim, who lives locally, had earlier been drinking in bars known to be popular with the gay community.
Canvas is mounted on a timber frame and includes a sturdy string for hanging it on the wall.
Detective Sergeant Simon Kinghorn, of Lothian and Borders Police, said the victim had been very traumatised.''What goes on in the whole Calton area is well known and it is easy to target.This man may have been picked out because he was gay, that does not mean to say his attackers were.'' The safety forum is due tomorrow to unveil its new action plan based on two years of research into attacks on gay and transgender people in the city.To be violated like this is a terrible experience for anyone.'' The police said they were keen to speak to a man seen in the area who was described as in his early 30s, 5ft 7ins, of medium build, and with fair straight hair.He was said to be wearing a light peach shirt and dark trousers.