As Comet Halley passed through Pisces on its approach towards the Sun, it warmed enough so that a tail just became visible. This 45 min AAT exposure was made on 4 x 5-inch Ektachrome EPD (200 ISO daylight) film, with the telescope tracking the comet. The white streaks are the background stars.

If proof was needed of the value of additive three-colour photography using glass plates, compare this image with AAT 46 made in the same session, with a similar total exposure time on separate hypersensitised glass plates take in red, green and blue light.