If you have a chuck for your rotary table the job is a piece of cake. A faced off square, deeply centred bar offcut makes the job quick and easy. Use a centre finder in the machine chuck for the greatest accuracy.
If you haven't got such a chuck, fit a large centre or even a live centre into the machine quill and centre it on the hole in the centre of the rotary table.
Centering up this way is quick and very accurate