Orbital Illumination Screen

Earth-shadow geometry · satellite & debris flare screening
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.