Air Force Project Blue Book Special Report 14 (Hynek's annotated copy)

Read from the scan by GLM-OCR; expect the odd misread word.

Temperature inversion reflections can give a return on a radar scope that is as sharp as that received from an aircraft. Speeds of these returns reportedly range from zero to fantastic rates The "objects" also appear to move in all directions Such sightings have resulted in many fruitless intercept efforts.

Bearing out the theory of temperature inversion reflection is an incident which occurred in January 1951 near Oakridge, Tennessee. Two Air Force aircraft attempted to intercept an unidentified "object" and actually established a radar "lock" on the object. Their altitude at the time was 7,000 feet. The unidentified object, according to their radar, appeared to be at an elevation of 10 to 25 degrees. Three passes were made in an attempt to close on the object. In each instance the pilots reported that their radar led them first upward and then down toward a specific point on the ground. (One scientific theory holds that light can be similarly reflected from a layer of warm air above the earth. If this proves to be correct, many visual night sightings could be accounted for.)

There are a small number of unexplained reports which involve a combination of seeing the object and detecting it on radar simultaneously. In each case the object appeared at night time and had the appearance of simple lights.

Ionized clouds have probably caused some unidentified radar returns. Thunderstorms are identifiable by radar, and radar is used aboard some aircraft and ships to avoid them. Radar returns have also been received from birds, ice formations in the air, balloons, ground reflections, frequency interference between other radar stations, and windborne objects. Obviously such returns are very difficult to identify, especially when they occur during darkness.

As stated earlier, the difficulty of evaluating reports of all types is based largely upon the lack of basic data surrounding the sighting. It is felt that the detailed questionnaire will remedy the situation in part.

In addition, special photographic equipment has been developed for distribution to selected air base control towers and Air Defense Command radar sites. This equipment consists of a diffraction grating camera which separates light into its component parts (spectrum) and registers them on film. The principle involved is that used by astronomers in determining the composition of the stars. In this manner Air Force scientists may be able to determine the source of unidentified lights. As yet, no photographs from this camera have been received.

There have been some misconceptions concerning the Air Force handling of "flying saucer" reports. One of these misconceptions is that the Air Force is either withholding "flying saucer" information from the public or cloaking it beneath a security classification. This is untrue.