Comet Hale–Bopp

Comet Hale–Bopp

Comet Hale–Bopp was the most widely observed comet of the 20th century. It was visible to the naked eye for a record 18 months, twice as long as the Great Comet of 1811, the previous record holder. The comet was discovered independently on July 23, 1995, by two observers, Alan Hale and Thomas Bopp, both in the United States. It met or exceeded most predictions when it passed perihelion on April 1, 1997.

About Comet Hale–Bopp in brief

Summary Comet Hale–BoppComet Hale–Bopp was perhaps the most widely observed comet of the 20th century. It was visible to the naked eye for a record 18 months, twice as long as the Great Comet of 1811, the previous record holder. The comet was discovered independently on July 23, 1995, by two observers, Alan Hale and Thomas Bopp, both in the United States. It met or exceeded most predictions when it passed perihelion on April 1, 1997, reaching about magnitude –1. 8. The Internet played a large role in encouraging the unprecedented public interest in the comet. As it approached the Sun in February, it continued to brighten, shining at 2ndndnd magnitude. On March 9, a solar eclipse in China, Mongolia and Siberia allowed there to see the comet in daytime in the daytime. It had its closest approach to Earth on March 22, 1997 at a distance of 315 AU, at a time when the Sun was 315 AU from the Earth. It is the only comet to have been discovered by amateurs at such a distance from the Sun, and the only one to have had an observable coma. It has been dubbed the ‘great comet of 1997’ by some astronomers, and is still visible to this day in the night sky. The most recent sighting of the comet was in January 1998, when it was visible at a magnitude of 10.5 in the constellation of Sagittarius. It lay near the globular cluster M70 in the sky, about 13 AU from the sun, a distance at which most comets are essentially unobservable. It also had a nucleus that was 60±20 kilometres in diameter, approximately six times the size of Halley, and appeared to be moving at a rate of about 1,000 miles per hour.

It became visible in May 1996, and although its rate of brightening slowed considerably during the latter half of that year, scientists were still cautiously optimistic that it would become very bright. In December 1996, it reappeared in January 1997, already bright enough to be seen by anyone who looked for it, even large cities with light-polluted skies. It passed close to the Sun again in February 1997, and by March 1997, it was at its closest point to Earth, at 315 AU. It then passed close by again in April 1997, at 1nd magnitude, about 2ndagnitude, and continued to shine for the rest of the year. The last time it was seen in the same way was in April 1998, at magnitude –2.5. It died in July 1998, and was never seen again in the near future. It remains one of the brightest comets seen for many decades, and has been called the ‘comet of the century’ or ‘the great comet of 20th Century’ It was discovered by two amateur astronomers in the U.S. in July 1995. Hale first established that there was no other deep-sky object near M70, and then consulted a directory of known comets, finding that none were known to be in this area of the sky. Once he had established that the object was moving relative to the background stars, he emailed the Central Bureau for Astronomical Telegrams.