The eclipse of the sun that will cross New England tomorrow, reaching maximum at 5:47 EDT (Boston), presents a unique opportunity for amateur astronomers to view and record a rare astronomical event.
Danger of eye-burn from infra-red radiation cannot be over-emphasized, however. Smoked or dark glasses are inadequate protection for the eyes, and use of them often leads to serious eye damage.
The cheapest and simplest protection for direct viewing throughout the eclipse is a filter made from two layers of exposed and developed black and white film.
Even greater protection is possible with a simple pin-hole camera made from two pieces of white cardboard. Light falls through a small hole in one and is focused on the other, where it can be viewed without looking directly at the sun.
For photographing the eclipse any camera can be used, but the longer the focal length the larger the sun's image will be. The camera also must be protected from the sun--use small lens openings and neutral-density filters throughout the partial phases.
Photographers who remain in Boston during the event (where the eclipse will only be 94.4 per cent of maximum), can record two interesting phenomena. By making a series of exposures at five-minute intervals on the same film, one can obtain a record of the partial phases.
Those who are willing to fight the traffic to and from Maine this weekend might have clear sky for the 50 seconds of totality. If so, the two interesting solar phenomena that can be photographed are Bailey's Beads, which occur for a second just before and just after totality when light breaks through the valleys on the moon's rim, and the solar corona.