Run · Incident 88: the Hackensack disc, 3 August 1947
Teterboro wind, sun and size check for the Hackensack object
Wind-drift and angular-size check for a low sighting: Course minus downwind (degrees).
Result
Result. The wind at 7 and 8 pm was from the south-west at 2.6 m/s under a clear sky, and the reported northward course lies 41 degrees left of downwind; a 0.3 m balloon at 60 m matches the reported angular size and would cross the sky three times faster than the witnesses' own size-distance estimate implies.
Test · estimate [95% interval]Against the null and the answersVerdict
Reported course minus downwind direction, 3 Aug 1947 eveningdegrees
−41.4
One course reconstructed from landmarks by one witness; no error was recorded, so no interval can be computed.
Needs an interval
Estimate, 68% interval (thick) and 95% (thin). Rule declared with the run: Set before the run: rule out free drift if the course lies more than 60 degrees from downwind.
What it used and found
ANS
Figures 2
Figure 1
The wind settled into a light south-westerly before the sighting and held through it
Teterboro Airport hourly wind speed, 3 August 1947, local time (EDT); direction 180-225 degrees throughout
wind speed
Drawn by the site
Figure 2
A small balloon 60 m away looks the size the witnesses described and crosses the sky three times faster
Angular size and drift rate in a 3.9 m/s wind for the witnesses' estimates and for a 0.3 m balloon
angular size (deg)drift rate (deg/s)
Drawn by the site
Parameters
station = Teterboro 99999994741, observer = [40.8935, -74.049], course_to = [40.991, -74.051], window_utc = 1947-08-03T16 to 1947-08-04T02, course_from = [40.859, -74.062], wind_profile = 1/7 power law from 10 m, reported_height_m = 183
Cite it
Mysteries Department. (2026). Teterboro wind, sun and size check for the Hackensack object [Run RUN0DFY94JHJTNT]. https://mysteriesdept.com/r/RUN0DFY94JHJTNT
@misc{mysteriesdept_run0dfy94jhjtnt,
title = {Teterboro wind, sun and size check for the Hackensack object},
author = {{Mysteries Department}},
year = {2026},
note = {Run, catalog key RUN0DFY94JHJTNT},
url = {https://mysteriesdept.com/r/RUN0DFY94JHJTNT}
}