Tarawa UFO

There has been a lot of talk about UFO's lately. With this in mind, my father wrote in a letter of 7 August 1965, from Tarawa, to his mother in Yorkshire:

"We are all agog here with a strange object that floats in the sky over the lagoon. It is there most nights and has no reasonable explanation. It looks like a large star, but it is obviously too low for that, and not high enough to be a satellite. It glows with a brilliant white light, sometimes hangs motionless and sometimes moves slowly across the sky. The light is so bright that it lights the lagoon, but you can see nothing that could hold it up and nothing that could generate such a bright light."

OBSERVATION: I remember this light. What was it? I have read various possible explanations. What seems most plausible to me is that the Allies were testing a means of lighting up islands for night-time warfare. The Battle of Tarawa was just 22 years before.