Abstract

Halley’s Comet has been under surveillance since it was spotted with an advanced detector on the 200-in. telescope in October 1982. It has since shown unexpected variations. We want to know the nature of the frozen nucleus of the comet and the mostly unidentified parent molecules that compose it. When the comet is near perihelion in February, viewing conditions will be unfavorable from the ground, due to the comet’s proximity to the sun, but the Solar Maximum Mission and Pioneer Venus Orbiter will provide needed observations. In March, as the comet crosses the plane of the earth’s orbit, it will be explored by European, Japanese, and Soviet space probes as the Astro 1 battery of telescopes and cameras, operated by astronomers flying aboard the Space Shuttle, makes sophisticated analytical measurements from earth orbit. In late 1986, 1987, and afterward, as Halley’s Comet heads back toward the far reaches of the solar system, to return in 2061, the Hubble Space Telescope will follow the receding object as it passes beyond the reach of detectors on the ground. These modern studies are summarized in the context of the rich lore (artistic, historic, social, and scientific) of ancient and modern observations of Halley’s Comet, including the recent discovery of Babylonian observations from 164 B.C. that enable astronomers to refine the orbital calculations. Finally, viewing conditions for observers at various latitudes on the earth are summarized.

© 1985 Optical Society of America