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Sundial (2D)

Interactive 2D horizontal sundial: tune latitude, time of day and day of year to see correctly-spaced hour lines, the gnomon's shadow, and the equation-of-time gap between sundial time and clock time.

Physics & Mechanics2DModerate60 FPS⇄ 3D version

A flat 2D horizontal sundial: drag latitude to reshape the hour-line fan, drag the clock-time slider to swing the gnomon's shadow across it, and drag day-of-year to watch the equation-of-time gap between sundial time and clock time change — traced live as a point moving around the analemma strip below.

⚙ Under the hood

A 2D horizontal sundial where sliders set latitude, clock time and day of year: watch the correctly-spaced hour-line fan, the gnomon's shadow sweep across it, and the equation-of-time gap between sundial time and clock time trace live around the analemma.

sundialgnomonhour angleequation of timeanalemmasolar declination

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install