Astronomers no longer must wait for the few minutes of a solar eclipse, but can produce their own, using a technique described by Donald H. Menzel, Paine Professor of Practical Astronomy, in a book published today.
Menzel's Our Sun presents information about the sun, gained since the invention of the coronagraph or artificial "sun-eclipser." With it, astronomers can create an "eclipse" in the laboratory every clear day and record it on film.
In the device a disk is placed where an image of the sun and its corona is focused by a lens. This disk acts like the moon during a natural eclipse of the sun by blocking out or eclipsing the bright solar disk.
Tomorrow morning Menzel will see the real thing, weather permitting, when he takes his Freshman Seminar students and Observatory officials in a DC-6 to view a natural eclipse, the first in the Boston area for 300 years. It requires the shortest expedition ever for Harvard astronomers to study a solar eclipse.