UFO Sidereal Histogram
At any given date, time and place, some part of the stellar sphere is directly overhead, at the local meridian. Astronomers divide the sky into 24 hours of Right Ascension (RA). By convention, the Vernal Equinox in Pisces is zero hours RA.This display counts UFO sightings for each longitudinal hour-zone. North-South "Declination" is disregarded here.
There is a notable bulge between 19 - 21 hours RA. This roughly corresponds to that slice of sky where Cygnus, Delphinus, and Capricorn are found, including the Galactic Center.
See this special study which attempts to isolate the causes of the apparent anomaly.
Special Sidereal Study