A star-tracker rotates the camera at the same speed as the Earth, but in the opposite direction. It has the visual effect of stabilizing the sky. Usually, star-trackers are used to stabilize the camera during a long exposure, to avoid blurry or streaked stars in the image.The purpose of this video is to help us visualize the Earth’s rotation. It’s something we know is happening, but is not something we directly perceive.If you enjoyed this post, please give it a ❤️ and check out @sciencefunn for