The 1986 apparition of Halley's Comet was the least favourable on record. In February 1986, the comet and the Earth were on opposite sides of the Sun, creating the worst possible viewing circumstances for Earth observers during the previous 2,000 years. Halley's closest approach was 0.42 AU. Additionally, increased light pollution from urbanization caused many people to fail in attempts to see the comet. With the help of binoculars, observation from areas outside cities was more successful. Further, the comet appeared brightest when it was almost invisible from the northern hemisphere in March and April 1986, with best opportunities occurring when the comet could be sighted close to the horizon at dawn and dusk, if not obscured by clouds.