A colleague asked me whether the trailing effect you see on the seconds hand was a photography trick, or something actually visible to the human eye.
![](https://i0.wp.com/oscilloclock.com/wp-content/uploads/2012/07/Trailing-Effect-.jpg?resize=280%2C177&ssl=1)
Yes, the trailing effect is real, and it’s thanks to a characteristic of the CRT’s phosphor screen called persistence.
(more…)