The height of what will reportedly be the first shot is so great that, for the first time, the residents of a large city, Honolulu, will be able to see the fireball of a hydrogen bomb at the instant of explosion. In 1958, a shot fired forty-eight miles above Johnston Island produced a flash visible in Hawaii, but the point of detonation could not be seen.
This time it will be well above the horizon. However, the distance of some 950 miles from Honolulu to the bomb, plus the atmosphere's filtering effects along the last part of the light's path, is expected to protect Hawaiians from eye damage.
The problem has nevertheless been sufficiently serious to require consultations with eye specialists. It was recalled that in the 1958 shot, the eyes of experimental rabbits were burned at a range of 370 miles. The bomb's release of energy is so swift that there is not time to blink.
The specialists were unable to agree on what, exactly, was a safe distance, for no adequate experiments have been carried out on human eyes. Nevertheless, those conducting the tests feel sure that Hawaiians will be safe from harm. --From The New York Times, April 28, 1962