UFO research

Some researchers recommend that observations be classified according to the features of the phenomenon or object that are reported or recorded. Typical categories include:

* Saucer, toy-top, or disk-shaped "craft" without visible or audible propulsion. (day and night)
* Large triangular "craft" or triangular light pattern
* Cigar-shaped "craft" with lighted windows (Meteor fireballs are sometimes reported this way, but are very different phenomena).
* Other: chevrons, equilateral triangles, spheres (usually reported to be shining, glowing at night), domes, diamonds, shapeless black masses, eggs, and cylinders.