star angel HALLEY

Halley's Comet or Comet Halley,.officially designated Halley, is the best-known of the short-period comets and is visible from Earth every 75–76 years.^[ Halley is the only short-period comet that is clearly visible to the naked eye from Earth, and thus the only naked-eye comet that might appear twice in a human lifetime.Other naked-eye comets may be brighter and more spectacular, but will appear only once in thousands of years..The English astronomer Edmund Halley was a good friend of Isaac Newton. In 1705 he used Newton's new theory of gravitation to determine the orbits of comets from their recorded positions in the sky as a function of time. He found that the bright comets of 1531, 1607, and 1682 had almost the same orbits, and when he accounted for the gravitational perturbation on the cometary orbits from Jupiter and Saturn, he concluded that these were different appearances of the same comet. He then used his gravitational calculations to predict the return of this comet in 1758.