HELSINKI, Finland (AP) _ Thousands of Finn and foreign skygazers converged Friday on eastern Finland to await a total solar eclipse in this land of the midnight sun.

Hundreds were expected at Joensuu, a small town about 50 miles from the Soviet border. Ten months ago, the town hired an eclipse secretary to handle the arrangements.

Observation points have been set up on hills outside Joensuu.

Local flights have been scheduled in case clouds make viewing impossible on the ground. Finnair, the national airline, will run an observation flight from Helsinki during the eclipse.

The eclipse starts at 4:03 a.m. Sunday (9:03 p.m. EDT Saturday) in Helsinki. At that time, the moon will begin gradually moving between the Earth and the sun.

The total eclipse will last 83 seconds. It begins at 4:52 a.m., 16 minutes after sunrise.

At that time, the sun will be only 1 degree above the horizon. The sun rises unusually early during summer in the extreme northern latitudes where Finland is located. The sun comes up unusally late during winter.

After the total phase of the eclipse, the moon will move away, uncovering more and more of the sun. The eclipse ends in Helsinki at 5:45 a.m.

The eclipse will be total in an arc about 125 miles wide from the northern Baltic Sea and southeast Finland, across the Kola Peninsula and northeast Soviet Union, to the Aleutian Islands near Alaska.

Scientists will conduct several experiments during the eclipse, including gravity test measurements of the radius of the sun. However, scientific interest in this eclipse has been less than in longer eclipses, such as the seven-minute eclipse seen from northern Kenya on June 30, 1973.

Seppo Linnaluoto of the Ursa Astronomical Association said the best place for observations of this eclipse will be the northeast Soviet Union. The best place in Finland will be the Joensuu-Ilomantsi area, he said.

''Many Finns will take the opportunity to see the event, especially as this might be the only chance they get in their lifetime,'' said travel agent Tuija Kivilinna.

''But we have lots of hotel reservations from abroad as well, even from United States, Canada, New Zealand and Japan.''