Opening the Dome

Sunset at Paranal was the colour of a peach. Then the sky went red, then violet, then deep blue.

At half past six, the dome of UT1 began to open.

Polly was on the catwalk above. The slit was twenty metres tall. It opened slowly. Inside, the dome was dark.

The shape inside was not like most telescopes. It looked like a huge hospital machine the size of a house. The main mirror was 8.2 metres across. It was made of a special glass. It was polished very smooth in Germany over five years. Then it came here on a ship and a truck.

An astronomer was at a desk with eight screens. Her name was Camila Vargas. She was from southern Chile. She had worked here for four years.

Camila was setting up. "First, we focus," she said. "The mirror gets a little warped every day by gravity and heat. We adjust it using 150 small parts that push on the back of the glass. We do this every few minutes during the night."

The dome rotated to a new patch of sky. Twenty-five thousand tons of steel turned smoothly. Polly felt the catwalk tilt.

The first stars came out. Then the Milky Way. The Atacama sky was not like the sky at other places. It was more. More stars. Brighter. Deeper.

Camila looked up. "OK. We are open."