By December, 1985, the long-anticipated brightening of Halley's comet was well under way, and early that month a faint tail was detected as it approached the sun. This picture was taken by the Anglo-Australian Telescope early in the month and was the first to show it. The image combines exposures in red and green light (20 and 15 minutes respectively) and has been enhance to emphasise the tail. The background stars appear as streaks as the telescope followed its motion during the exposure, with a short gap between plate changes.

The diffuse coma appears small here because of the action of sunlight on gases evaporated from the icy nucleus produces a predominantly blue halo, while the tail is made of dust grains shining by reflected sunlight. Both tails became much more obvious and differentiated after perihelion passage (after its closest approach to the sun), and photographs of this period are elsewhere in this series. This image was made by combining two sequential AAT plates taken in red and green light, hence the double star trails.