This article is from the Alien Visitors FAQ, by CRAM: The Cyberspatial Reality Advancement Movement email@example.com with numerous contributions by others.
The main classification of UFO reports in use is based upon one used by
Dr J. Allen Hynek in his book "The UFO Experience" (Aberlard-Schuman 1972).
It should be noted that many other classification systems have been devised
by other researchers. Briefly the Hynek system (with the most commonly used
extensions) is :
NL (nocturnal light)
A simple visual sighting of a unidentified flying light seen at night.
This group contains 35 to 40 percent of all UFO reports.
ND (nocturnal disc)
A simple visual sighting of a unidentified flying extended or structured
light source seen at night. (This is an extension to Hynek's system).
DD (daylight disc)
A simple visual sighting of a UFO with distinct shape seen during the day.
UFOs detected by radar alone. In more recent years fewer cases involving
radar have hit the press. This could be because of a number of factors,
for example the government is better at suppressing these reports, or there
has been a change in the nature of the phenomenon which makes it less
detectable or that many of the early reports were the result of spurious
events and false positives which are handled better by more modern
Radar Visual Cases
UFOs observed visually whilst being simulataneously on radar. From Hynek's
study these make up 1 to 2% of reports.
Close Encounters of the first kind (CE1, CEI)
As first defined by Hynek, a CE1 is an observation of a UFO within 150
Close Encounters of the second kind (CE2, CEII)
A UFO which leaves some form of physical evidence
Example: A burn where the UFO appeared to touch the ground or the finding
of material of unknown makeup.
Close Encounters of the third kind (CE3, CEIII)
A visual sighting of an occupant or entity associated with a UFO. An
analysis by Hynek of 650 reports found only 1% to be CE3. These entities
are sometimes called UFOnauts.
As well as entities seen inside a craft, entities have been described as
sampling soil, rocks and plants or might communicate with the witness.
These witnesses are sometimes referred to as contactees. As well as
communication, the witness may report that they were invited on board
a craft or even taken for a trip.
Although included with UFOs, when dealing with contactees the researcher
is dealing with a case of something clearly identified by the witness as
some form of craft (without specifying the origin of that craft). Strictly
speaking the object is no longer unidentified.
(Close Encounters beyond the third kind are extensions to the basic Hynek
system. Different authors have used the same designation to mean different
Close Encounters of the fourth kind (CE4, CEIV)
An abduction of an individual by an alien being or race. The most famous
of these being the abduction of Betty and Barney Hill in September 1961.
(Hynek included this case in his CE3 category.) Although in recent
years abductions have, because of their spectacular nature, received a
great deal of publicity, they constitute only a small proportion of all
Close Encounters of the fifth kind (CE5, CEV)
Sometimes used to represent a direct contact or communication with alien
being or race. For example: Billie Meier with the Pleiadians, U.S.Govt.
with the Greys, or channeling.
Other researchers have used this classification for strange beings that
have been reported, but without the obvious presence of a 'craft'. These
beings are generally seen in the witnesses house at night. Their
description is similar to the beings seen associated with UFOs in
abduction and contactee cases. Sometimes they are called 'bedroom
visitors', the same set of reports have been classified as CE0 (zero) and
CE9 by other groups of researchers.
It must be remembered that, after careful investigation, over 90% of UFO
reports can be reasonably explained as manmade or natural phenomena. The
late Charles H. Gibbs-Smith (aviation historian to the Victoria and Albert
Museum in London) had something he called Gibbs-Smith's rule which is worth
keeping in mind when studying UFO reports. It states that "the strangeness
of a case increases in proportion to the distance, in either time or
geographical distance, between the investigator and the location of the