This tool scans a video of the Moon for impact flashes — the brief glints of light produced when a meteoroid strikes the lunar surface. Everything runs in your browser; the video is never uploaded.
1. Remove the steady background
The Moon drifts and jitters slightly between frames (tracking error, atmosphere, a little rotation) and the earthshine glow changes slowly. The software keeps a rolling average of recent frames as a model of the quiet, slowly-changing scene, then subtracts it from the current frame. What survives is only what suddenly changed — the steady Moon largely cancels out.
2. Keep only compact bright spots
Camera shake smears brightness across wide areas, which looks like change everywhere. A top-hat filter subtracts a blurred copy of the difference image so broad, soft glows disappear and only small, sharply-peaked bright points remain — the shape an impact flash makes.
3. Group pixels into blobs
Neighbouring bright pixels are joined into blobs. Each blob's position, size, shape and peak brightness are measured.
4. Reject look-alikes
A blob is dismissed unless it behaves like a real flash:
- Point-like, not a streak — thin, elongated shimmer along the Moon's bright edge is rejected.
- Right size — not a single hot pixel, not a huge brightening (cloud, focus change, glare).
- Brief and transient — it must rise sharply and then fade within the duration limits; steady lights (stars, satellites) are rejected.
- Strong enough — its peak must clear a confidence threshold set by the Sensitivity control.
5. Track and report
Surviving blobs are linked across consecutive frames into a single event, then reported with the location, the frame(s) it appears in, duration, size and peak brightness. The method follows established lunar-flash work such as NASA's impact-flash citizen science and the ALFI project.
This is a screening tool, not confirmation. A real lunar impact must be verified against a second simultaneous recording to rule out satellites, cosmic-ray hits, and camera noise.