The Humming Arrow
A Doppler Card — one tone, one track, one formula. The ticks are the crests; the bracket is the ruler. Listen to the geometry.
Press LAUNCH — the arrow takes a steady tone across the sky.
Speeds and distances are exaggerated for legibility; the ratios obey the true formula.
The ticks mark each wavefront's crest as it crosses the flight line; the brackets measure the gaps between them.
Schematic, not to scale. Hover the arrow, ticks, observer, stars, or the trace for terse notes and sources.
