"The surface of the Earth is the shore of the cosmic ocean... Recently, we've managed to wade a little way out, and the water seems inviting." - Carl Sagan
The NTT spinning like a top
This dynamic image shows the New Technology Telescope (NTT) located at ESO’s La Silla Observatory in Chile. The distinctively shaped enclosure of the telescope appears blurred by movement in the picture, as the telescope rotates to point at its desired target. The photo was taken with a 30-second exposure.
One of the first things you notice in this picture is that the telescope building has a peculiar angular shape on the outside, rather than the more common rounded dome design usually seen. Its design features have been much copied, including by ESO’s Very Large Telescope, but they were groundbreaking when the telescope was inaugurated in 1989.
The NTT’s revolutionary design targets optimal image quality, for instance, through carefully controlled ventilation, which optimises airflow across the NTT, minimising the blurring caused by air turbulence inside. Just visible in the blur of this image are the large flaps that form a key part of this system.
Another feature that was advanced at the time of its construction is the NTT’s mirror. While, at 3.58 metres in diameter, it was never considered particularly large, its design was highly innovative. The mirror is flexible, and can be adjusted in real time to maintain a perfect shape, so no flexing or sagging can harm the image quality. ESO and the NTT were pioneers in using this technology, called active optics, and it is now a standard feature of modern telescopes.
Image credit: ESO/M. Tewes