Amazing as it sounds, but fortunately, for the Muslims of the world, it is an established fact.
Have a look at a map of the world
And you will find Indonesia on the eastern side of the earth. The major cities of Indonesia are Java, Sumatra, Borneo and Saibil. As soon as dawn breaks on the eastern side of Saibil, at approximately 5:30 am local time, Fajar Azaan begins.