A star tracker is a device that astrophotographers use to take long exposure photos of the night sky. The camera is mounted on the tracker and the tracker is aligned with rotation axis of the Earth. Then the tracker moves the camera and keeps it aligned with the sky.
Without a tracker long exposure shots of more than 30 sec will capture the movement of the stars (known as star trails). Therefore, it is very hard to take a long exposure photo of the sky without a tracker. However, using a tracker, the camera remains aligned with the stars in the frame and longer exposures are possible.
O-Falak is a star tracker designed to make long exposure photography of the sky possible. I have some good pictures to show.
Design, Arduino, Photography