Project Blue Book Case #1813. On August 4, 1952, witnesses in Mount Vernon, New York — a city immediately north of the Bronx, just 15 miles from midtown Manhattan — observed a bright object in the sky. The sighting placed an unknown squarely within the New York metropolitan area's vast suburban ring.
Mount Vernon's proximity to New York City meant it sat beneath one of the world's most congested airspaces. LaGuardia Airport was approximately 10 miles to the south, and the approach and departure corridors for the region's airports created a near-constant procession of commercial aircraft overhead. Residents were extraordinarily experienced at recognizing routine air traffic.
August 1952 was during the peak of the great wave. The New York metropolitan area, with its dense population and busy airspace, contributed multiple cases during this period. Each New York-area case represented a sighting that had survived the initial filter of being in a place where aircraft were ubiquitous — witnesses had to see something genuinely unusual to bother reporting it.
The object's brightness and behavior distinguished it from the constant flow of commercial traffic. It did not exhibit the characteristic navigation light patterns or flight behaviors of aircraft operating in the New York terminal area.
Air traffic records were checked. No aircraft correlated with the sighting. The case was classified "Unknown."