OUR only record of how starry nights have changed over the past century is in
danger of vanishing. Astronomers are warning that most old photographs of the
night sky are disintegrating, and an urgent programme to store them in
electronic form is needed.
Today, state-of-the-art telescopes record vast amounts of data digitally on
computer servers. But until the 1990s, most observations were recorded on
photographic plates and so are not available in digital form. The world’s
astronomical archives contain more than 2 million photographic plates, some more
than a century old.
They hold our only information about how stars and…
