Fun with exposure / 42 degrees

The Foucault Pendulum in the central rotunda of Griffith Observatory. This 240-pound ball swings on a cable over a this circular pit with a lighted ring around the perimeter.

Here's two virtually identical shots of the ball. Both use the same aperture setting (F/3.5, for the photographically inclined).

Here's what it looks like with a 1/15 second exposure:


Here's what it looks like with a 1/125 second exposure:


Hey look: That lighted ring is divided into 42 sections (numbered 0 - 41). All because we let the lens be exposed to the light for 1/110th of a second less (shorter than the blink of an eye).

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"Photo" means light, doesn't it? Imagine that: Photography depends entirely on light.

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Speaking of the 42 sections: They're not only designated on the lighted ring:

But also around the upper lip of the wall around the pit (directly opposite the corresponding number on the ring below):