The device that tracks the movement of the sun is called a sun tracker.

There are different types of sun trackers, but they all work on the same principle:

* Passive Sun Trackers: These trackers use the sun's heat to move a panel or mirror to follow the sun. This is often seen in solar panels.

* Active Sun Trackers: These trackers use sensors to detect the sun's position and then move the panel or mirror accordingly. This type of tracker is often more accurate and can be used in a wider range of applications.

Some common examples of sun trackers include:

* Solar panels used for generating electricity.

* Solar concentrators used for heating water or generating electricity.

* Telescopes used for observing the sun.

Note: A sundial is not a sun tracker. While it uses the sun's position to tell time, it doesn't actively move to track the sun.