Linda McMan, age 14, of  Minden, La. for her question:

How old is astronomy?

Astronomy began when early man looked up in wonder at the heavens. The records of his star gazing go back to prehistory. He noted that the stars form eternal patterns, which move with the seasons. Before the dawn of history 48 constellations had been named and the Chaldcans had charted the Saros ‑ the 19‑year eclipse cycle.

Records and charts from endless star gazing were necessary for the astronomy which was to follow. This basic chore work was done by countless unknown star gazers. The early Greeks tried to find a system in the heavens. In 250 B.C., Aristarchus of Samos taught that the sun stood still and that the earth went around it. He had but a few followers and the idea went out of style when the greet Aristotle said the earth was the center of everything.

In 150 B.C. the Greek Hipparchus made the first catalogue of the stars. He tried to chart the entire heavens. Then came Ptolemy of Alexandria, greatest of all the early astronomers. In 150 A.D., he made a complete star atlas. He also charted 1,030 stars in order of brightness. He listed them in six magnitudes with 20 stars in the first magnitude.

Then followed the Dark Ages in which no new work was done. The Arabs kept alive the valuable work of Ptolemy lie had believed, along with Aristotle, that the earth was the center of the Universe. This idea prevailed for another 14 centuries.

The old idea was finally challenged by Nikolaus Kopernik, a Polish churchman. We know him as Copernicus. He studied the heavens and the old charts. He said that the earth and all the planets might be revolving around the sun. He said that if our eyes could. see whether Venus had phases like the moon we would know for sure that it was so.

Meantime, Tycho Brahe was making new charts from his observatory near Elsinore in Denmark. He made a new star atlas in which he included the South Pole stars. Kepler his pupil, made records of the moving planets. In Italy the young Galileo and the great Da Vinci had become star gazers.

So matters stood when a Dutch maker of eyeglasses invented the telescopes Galileo was the first to recognize it as the eyes Copernicus had wanted. The winter of 1609 and 1610 was the greatest time astronomy had ever known, Galileo, from the roofs of Florence, stared at the heavens through a little telescope. He recorded, with deep emotion, the wonders he saw. Yes, Venus dogs have phases. Copernicus was right. The planets do revolve around the sun.

The year that Galileo died Isaac Newton was born in England. His great mind took astronomy through its next strides. The charts of Tycho, the records of Kepler, the theory of Copernicus, the work of Galileo and all the ancient star gazing were drawn together at last. For Newton worked out the laws by which the heavenly bodies moved in their orbits. These laws apply to the Sputniks, Jupiters and Vanguards launched 230 years after his death.