Field tool · geometric model Screens one hypothesis only
When & where
Enter the offset actually in force that night, daylight saving included. Arizona is −7 year round; most of the US is −4 to −7.
West longitude is negative. Use the witness's position, not the nearest town centre.
Where the object was
Arm extended: fist ≈ 10°, open hand span ≈ 20°, three fingers ≈ 5°, thumb ≈ 2°.
Enter the bearing as read. Add declination only if the reading came from a magnetic compass — east is positive. Leave at 0 for a true bearing.
Behaviour (optional)
A very large number, or blank, means it appeared to hold still. Satellite motion has both a ceiling and a floor at any given altitude, so this tests in both directions.