The way we were - vintage images of our first glimpse of comet 67P 45 years ago
Back in 1969, long before digital imaging, scientists had to rely on cumbersome techniques to image astronomical objects. It was a painstaking process of making lengthy exposures of the same part of the sky on glass plates that were coated with a light-sensitive emulsion.
Glass-backed plates were used instead of film as they were less likely to shrink or deform.
It was only by comparing successive plates that astronomers could find moving objects.
Astronomer Klim Churyumov and Svetlana Gerasimenko, one of his researchers, were on a comet-hunting expedition at Alma-Ata Observatory, Kazakhstan, when they they discovered 67P, first catching sight of it as it appears in the image above.
While now, with the Philae landing tethered to the comet's surface, we can see individual rocks on the surface in sharp relief, then it looked like no more than a piece of dandruff on a dinner jacket.
The two images, taken by Churyumov on 21 September 1969 with a wide-angle Schmidt telescope, were exposed a short time apart. It shows 67P as a fuzzy object shifting position slightly.