The largest telescope ever to be flown above the surface of the earth will be launched by Harvard in conjunction with the Smithsonian Astrophysical Observatory and the University of Arizona this month.

The telescope will be used to study unexplained sources of far-infrared radiation at the center of the Milky Way; a helium-filled balloon, 250 feet in diameter, will carry it to an altitude of about 95,000 feet.

The balloon will be launched from Palestine, Texas later this month.

The $140,000 needed for the Infrared Telescope Balloon Project will come from Harvard College Observatory and the Smithsonian Astrophysical Observatory funds. The University of Arizona is supplying the equipment.

This is the first time Harvard is using a balloon rather than a rocket for high altitude observations.

Cheap and Effective

A balloon is the only vehicle large enough to transport the 40-inch in diameter telescope. Robert W. Noyes, physicist at the Smithsonian Astrophysical Observatory said. In addition, a balloon can stay up longer--10-12 hours of observation is planned--it carries more instruments, and is cheaper.

Observation of far-infrared radiation is impossible to make from the ground because of obstructive water vapor. The balloon will rise above this vapor at an altitude of 18 miles, Noyes said.