colour sweep — 10 min stack sliding 1 min per frame, 60 fps; story of the night in 5 seconds
monochrome sweep — same window, greyscale (science view)
difference sweep — max(frame) − window mean; the sky floor, hot pixels, and cloud-glow cancel, leaving only trails and transients
detrans sweep — each 10 min window undistorted (k1,k2) and de-translated by the sky velocity, registering the 60 s streaks into one sharp high-SNR streak; stars stay tight as the night drifts past
detrans deep — registered frames averaged then background-subtracted (max SNR); pulls the faintest stars onto a clean dark sky, per 10 min window through the night