With modern computer programmes that can simulate trajectories and reconstruct the night sky thousands of years ago the researchers have established what the Planisphere tablet refers to. It is a copy of the night notebook of a Sumerian astronomer as he records the events in the sky before dawn on the 29 June 3123 BC (Julian calendar). Half the tablet records planet positions and cloud cover, the same as any other night, but the other half of the tablet records an object large enough for its shape to be noted even though it is still in space. The astronomers made an accurate note of its trajectory relative to the stars, which to an error better than one degree is consistent with an impact at Köfels. in this stylised map the sky has been divided into eight sections. It represents the night sky of 3-4 January 650 BC over Nineveh. The rectangular shape at the top has been identified as the constellation known today as Gemini and the stars contained with an oval shape are the Pleiade