Scientists Construct New Device for Sun Research

A group of Harvard scientists--working under a $280,000 grant from the National Aeronautics and Space Administration--has constructed a new device to gather data on the solar corona.

John L. Kohl, research associate at the Harvard Observatory and principal scientist for the program, conceived the "ultraviolet-light coronagraph." Edmond M. Reeves, lecturer on Astronomy, is directing its use.

Kohl said yesterday the coronagraph is expected to be launched in an unmanned sounding rocket in November to an altitude of 100 kilometers where it will gather and simultaneously transmit information.

The coronograph is designed to create an artificial solar eclipse, thereby permitting observation of the ultraviolet rays of the corona, the portion of the sun's atmosphere which extends well beyond the visible disk.

It is the first instrument of its kind. Previous coronographs have gauged only light from the visible spectrum.

Because the corona is only one-billionth as bright as the sun's visible disc, scientists have been able to observe only a very limited portion of the corona when the sun is not eclipsed. An extensive observation of the corona has occurred just once, during the 1970 total solar eclipse, by an expedition force led by Donald H. Menzel, former director of the Harvard Observatory.

The $280,000 stipend which NASA gave two months ago is the fourth annual grant NASA has provided the program since Reeves and Kohl proposed it in 1975.

Kohl said yesterday he expects further support from NASA after the first foray in November for additional launches and to upgrade the instrumentation.

Reality

Kohl described NASA's interest in the project as "purely academically based." He added. "It has nothing to do with the space-shot program."

The specific function of the coronagraph is to determine the wavelength distribution of the corona's ultraviolet rays in order to derive temperatures within the corona.

This data may help to explain solarterrestrial anomalies such as geomagnetic storms and solar wind streams.

Kohl said yesterday although the coronagraph is now a "complete instrument." it still needs "minor modifications and performance testing." The group will devote the next eight months to perfecting it.

For one of these tests, the research team has constructed an elaborate 50-foot vacuum tank in which the mission can be simulated