This is a full circular fisheye image of the night sky, showcasing the movement of the stars (star trail). The image is a composite of over 100 separate 30-second exposures, totaling just under 1 hour of movement. I used some editing tricks to get the trails to gradually increase in brightness so you can see the direction of movement.
You'll notice some of the brightest stars reflecting in the calm water, and the brighter band of stars at the top of the frame is the Milky Way. The North Star is also visible in the upper left at the center point of the spin.