Stonehenge may be "not so much an observatory as a monument" marking where early British skygazers discovered the regularity of the sun's motion, Owen J. Gingerich, professor of Astronomy and the History of Science, said last night.

Speaking before 600 people in the Science Center, Gingerich said he views theories about the astronomical sophistication of ancient peoples "with considerable skepticism."

Astronomers and archaeologists have long speculated that Stonehenge, a ring-like structure of tremendous stones built in southern England more than 4000 years ago, may have been a pre-historic astronomic research tool.

Although some experts have said Stonehenge's builders could predict solar eclipses by making observations from certain positions near the main ring, Gingerich said he is reluctant to accept such a theory. Even though eclipses can be roughly predicted with the stone formation, ancient peoples may not have observed this fact or understood the phenomenon, he added.

Gingerich said, however, at least one claim about Stonehenge is justified: 'the whole monument is lined up in the direction of the sun during the summer solstice." He added that Stonehenge's designers probably aligned the stones purposely to record the northernmost path of the sun.

Several similar structures in Scotland have more accurate alignments, Gingerich said. But he stressed that even these seemingly more sophisticated structures may not be so valuable as some scientists contend. The Scottish rings "would be truly wonderful if the whole area were not dotted with stones," he said.