Answer:
by providing biographical information about specific astronomers and their discoveries
Explanation:
Ball has written a book about the great astronomers and reveals that astronomy would not be what we know today without the lives of these men who have contributed so much to the development of this science. During the development of his book, Ball can refine the central idea by providing biographical information about specific astronomers and their findings, thus proving how important these men were and how they influenced astonomy.