Not all UFO organizations are using the same classification system across Europe or outside.
In order to give a quick glance, Euro Ufo Index is using a two-level classification.
The first level is the type, which is a simplified version of Hynek classification system, distinguishing:
– NL: nocturnal lights (distant lights or luminous sources)
– DD: daylight objects
– CE: close encounters (landings or less than 150 meters from the witness)
A fourth type (shown as a star: * ) was added for those reports (eg. photos, traces, instrumental recordings) which are not associated to a visual sighting.
The second level is the subtype, which is meant to highlight some special feature (which may have been the focus of special research or catalogues). Until an agreement is reached among participating organizations about a shared unified classification of such features, this column is provisional. An example is the coding system adopted by CISU for the Italian reports:
A : Astronomer witness
C : Contact/Communication
D : Defense implications (military witness)
E : Effects
F : Photographs
I : Instrumental Detection
L : Landing (Vallee Type 1)
M : Mass sightings
O : Odour
P : Pilot witness
R : Radar
S : Sound
T : Traces/residues
U : Uso (Water UFO)
V : Video/Film
W : skyWatch ongoing
3 : Humanoid (CE3)
4 : Abduction (CE4)
+ : Repeater witness