The Presque Isle Theodolite Light

The light hung over northern Maine through the night of 10–11 October 1952. Weather observers at two Air Force bases turned their theodolites on it and took elevation and azimuth readings for hours. They described "a circular orange object with four green lights nearby". The weather was clear. The Air Technical Intelligence Center wrote to commend the 4711th Air Defense Wing: "This is the first time such triangulation has been effected." A light fixed from two stations can in principle be placed in space.

What is on the record

The main source is a CIA memorandum to the Director of Central Intelligence from H. Marshall Chadwell, Assistant Director for Scientific Intelligence, typed on 18 December 1952 after his office visited ATIC. Its Tab A lists the case as "Bright Light sighted from Presque Isle and Limestone Air Force Bases, Maine", seen from 2300 to 0300 local time. Its verdict is short. The observed azimuths and elevations, set against the calculated position and motion of Jupiter, "leave little doubt that the observed object was actually Jupiter." The archive holds four copies of the memorandum.

A second CIA note records a call with Captain Edward J. Ruppelt of ATIC. At that stage Ruppelt suspected Saturn and planned a test sighting with the same theodolite.

Project Blue Book's own case file agrees with the memorandum. Its record card gives 2200 EST, four hours and "WX observers", with the conclusion "Was Jupiter". Before that answer ATIC had asked whether a high-altitude research balloon could have been overhead. The UFO historian Loren Gross, working from the base's report, writes that the two theodolite lines met about thirty miles off the coast at some 300,000 feet. That height, above the atmosphere, is what first excited Blue Book's analysts.

Why it sits where it does

L4 · OFFICIAL RECORD — a released government record names who saw it. The observers are the weather-station crews on duty at Presque Isle and Limestone Air Force Bases. No independent testimony sits beside the record in the archive. The record carries its own ordinary answer, and the tier measures sourcing rather than truth. The CIA and Blue Book called the light Jupiter; nothing in the archive disputes it.