File:Sweet Dreams, Halley! - Eso9008a.jpg

English: Comet Halley in February 1990. Famous Comet Halley, now receding from the Sun after its perihelion passage in early 1986, has recently entered into a state of hibernation which will last until shortly before the next passage in 2062.

This is main result of an extensive series of observations at the European Southern Observatory in late February 1990, during which the comet was imaged with an extremely sensitive CCD camera attached to the Danish 1.5 m telescope at La Silla. At this time Halley was 11.6 AU (1735 million km) and 12.5 AU (1870 million km) from the Earth and the Sun, respectively, that is well outside the orbit of the giant planet Saturn.

To see the faint light from the distant object, exposures totalling 980 min (16 hrs 20 min) were obtained. The ``negative picture shown here is a composite of 23 frames, each individually cleaned. The image of Halley at the centre is pointlike; the straight lines are trails of stars and galaxies in the field, because the telescope was set to follow the comet's motion. The mean, visual brightness of Halley during the observing period was 24.4 magnitude and brightness variations of 1.3 magnitude were seen.