Classifying UFOs


David Calvert

The Hynek UFO Classification System (HCS)

The first serious attempt at classifying UFOs came from the most influential figure in ufology, J Allen HynekJoseph Allen Hynek. A professor of Astronomy at North-western University, US, Hynek was employed in 1948 by the US Air Force to investigate UFO reports. As former head of Project Blue Book, he devised the following classification system, which has long been the ‘industry standard’. He initially divided UFO reports according to the distance from the observer – greater or less than 150 m. (500 ft.) – and then further subdivided these two sections into a total of six categories.


Nocturnal lights:

Light or lights seen at a distance. These may display various fluctuations in intensity, changes in colour and/or rapid acceleration, and sudden turns or directional changes. They frequently turn out to be no more than misidentifications of planets such as Venus or Jupiter, high altitude aircraft or meteors. Daylight (diurnal) discs: Often seen at a distance, and varying considerably in shape and size, may be disc, cigar or cylinder shaped, egg or acorn shaped (the former usually seen on a horizontal axis, the latter on a vertical axis). They may be spherical, ovate, irregular shapes or (as of late) large black triangles. They may or may not exhibit similar patterns of behaviour to nocturnal lights. Often the result of misidentified weather balloons, blimps, aircraft or even hoaxes.


Witnessed as a radar reflection and as a visual sighting by an independent observer. Stand-alone radar sightings are often written off due to the nature of false traces caused by natural phenomena such as flocks of birds, ground scatter (a reflected signal from high cloud), cloud banks and temperature inversions. Relatively rare, but important, they may provide instrumental evidence to support the visual aspect of the sighting.


CE I  (Close encounters of the first kind): Observations of phenomena with no interaction between UFO and witness or environment.

CE II (Close encounter of the second kind): The witnessing of physical effects on organic and non-organic, animate or inanimate objects. Such effects may include the disruption of car engines or other radio or electrical interference (due to the electromagnetic pulse (EMP) effect on the electrical circuits, diesel engines are not usually effected), broken tree limbs, scorched or flattened vegetation, imprints in the ground, scorched or newly exposed earth, and increased radiation levels or localised time anomalies.

CE III (Close encounters of the third kind): The witnessing of occupants in or around the UFO. There is a bone of contention concerning these so-called ‘contactee cases’. Hynek himself believed that such reports invariably came from pseudoreligious fanatics, and sceptics to add weight to these arguments often quote cases such as those of George Adamski, et al. To fully qualify for CE III status, the occupants of the UFO should either be witnessed or have verbal or some other communication with the witness. There may be displays of hostility by or towards the extraterrestrial biological entity (EBE) or by remote devices.

CE IV (Close encounter of the fourth kind):  Although this is not one of Hynek’s classifications per se, it is included as a later addition to the above and implies actual abduction by EBEs, in its literal sense of being abducted without the witness’s consent and/or knowledge. These encounters frequently begin with a CE II and the abductee may have no knowledge of the event until such time as regression therapy becomes necessary due to subsequent emotional or psychological disturbances.

The Valée Anomaly Classification System

Jacques ValleeDevised by Dr. Jacques Valée, a French-American graduate of Hynek’s astronomy course at North-western University, this system is now more widely used than Hynek’s system, as it is more specific for analytical purposes and narrows things down somewhat. Valée divided UFO reports into the various sections detailed below.

AN ratings are used to classify anomalous behaviour.

AN 1: Anomalies which have no lasting physical effects, such as amorphous or flashing lights, and unexplained explosions.

AN 2: Anomalies that do have lasting physical effects, such as poltergeists, materialised objects, areas of flattened grass, scorched ground, broken or damaged trees, crop circles, etc.

A 3: Anomalies that have entities associated with them, such as big foot, ghosts, yetis, spirits, elves, goblins, or other such mythical or legendary entities.

A 4:  Witness interaction with the AN 3 entities, including near-death experiences, religious miracles and visions, out-of-body experiences (OOBEs).

A 5: Reports of anomalies in which there are injuries and deaths, including spontaneous human combustion (SHC), unexplained wounds, or even ‘supernatural’ healing that may result from such an experience.

MA ratings are used to describe the behaviour of a UFO and are comparable with the Nocturnal Light, Daylight Disc, and Radar-Visual Hynek classifications.

MA 1: A UFO has been observed which travels in a discontinuous trajectory – rapid acceleration/deceleration, vertical climbs or drops, manoeuvres or loops.

MA 2: MA 1 plus any physical effects caused by the UFO as per AN 1 or AN 2.

MA 3: MA 1 plus any entities observed on board, e.g., the airship cases of the late 19th century.

MA 4: Manoeuvres that are accompanied by a sense of reality transformation for the witness.

MA 5: Manoeuvres resulting in the permanent injury of death of the witness.

FB ratings are used to describe the fly-by of an anomalous craft or object.

FB 1: A straightforward sighting of a UFO travelling in a straight line across the sky.

FB 2: FB 1 accompanied by other physical evidence.

FB 3: A fly-by where crew, pilots or other entities are observed on board.

FB 4: A fly-by whereby the witness has experienced a transformation of reality into the object or its occupants.

FB 5: A fly-by in which the witness suffers permanent injuries or even death.

CE ratings are used to describe close encounters, and are very similar to the Hynek close encounter classifications.

CE 1: UFO comes to within 150 m. of the witness, but the witness or the surrounding area suffers no after-effects.

CE 2: CE 1 that leaves landing traces, or temporary injuries to the witness.

CE 3: Entities have been observed on or within the UFO.

CE 4: The witness has undergone abduction.

CE 5: CE 3 that results in permanent psychological injuries to, or death of, the witness.


The SVP rating system is an important rating of credibility. ‘Marks’ out of four are awarded for the three categories of reliability (first number), site visit (second number), and possible explanations (third number). For example, if a rating of 330 was awarded, it would imply that the witness was at first-hand and reliable, the site was visited by a reliable investigator, but the sighting could be explained by natural or mundane causes, thus:

Source reliability rating: 

  •  Unknown or unreliable source = 0
  •  Report attributed to a source of unknown or unmeasured reliability = 1
  •  Reliable source – second-hand = 2
  •  Reliable source – first hand = 3
  •  First hand personal interview with the witness by a source of proven reliability = 4

Site visit rating:

  • No site visits, or answer unknown =
  • Site visit by a person not familiar with the phenomena =
  • Site visit by a person or persons familiar with the phenomena =
  • Site visit by a reliable investigator (s) with some experience =
  • Site visit by skilled analyst (s) = 4

Possible explanations rating:

  • Data consistent with one or more natural or mundane causes =0
  • Natural explanation requires only slight modification of the data = 1
  • Natural explanation requires major alteration of one parameter = 
  • Natural explanation requires major alteration of several parameters =
  • No natural explanation possible, given the evidence =4

© David Calvert 2011

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