Comet Hale-Bopp passed through the inner solar system in early 1997. It was admired in the sky by a substantial fraction of the world's population. It was the true image of a "classical" comet, with a bright head and an enormous, multi-coloured tail. Due to its fortuitous orbit, it remained visible in the evening sky during several months, with all the associated positive effects. Professional observers at large telescopes around the world gathered the richest data ever obtained from a single comet, amateurs at star parties in different countries made large numbers of beautiful images and hardly a day passed without media reports about the latest developments of this spectacular celestial phenomenon. It is no wonder that, as an extra bonus, the general interest in astronomy received a major boost on this occasion.
See the ESO Page on this particular comet at the special webpage, with links to image taken in 2001, when the comet was more than 2 billion kilometres away.
Comet 1996 B2 (Hyakutake) was one of the brightest comet in the sky. It passed within 15 million kilometres (0.1 AU) of the Earth on March 25, 1996, and reached its perihelion on May 1, 1996. More info on the ESO Page for Comet 1996 B2 (Hyakutake).
In 2003, 17 years after that passage, Comet Halley was again observed by the Very Large Telescope (VLT) at Paranal (Chile). It was then almost as far away as Neptune, the most distant giant planet in our system. At 4,200 million km from the Sun, Comet Halley had completed four-fifths of its travel towards the most distant point of this orbit. Read the details and see the image in ESO Photo Release 28/03.
In mid-July 1994, fragments of Comet Shoemaker-Levy 9 collided with Jupiter, the largest planet in the Solar System. The comet was discovered in March 1993, and its nucleus which may be likened with a "dirty snowball" of ice and dust, broken into more than 20 pieces during a close passage near Jupiter in July 1992. All of these fragments, which measure from a few hundred metres to a few kilometres in diameter, hit Jupiter during a period of about 5 1/2 days, starting July 16. Astronomers all over the world observed the associated phenomena with ground- and space-based astronomical instruments. Look for more details on the ESO page on Comet Shoemaker-Levy 9.
Comet LINEAR (C/1999 S4)
On the night of July 25, 2000, this comet was seen to undergo a rapid change. The initially compact comet nucleus evolved into a fuzzy, extended and much fainter object. The comet was disintegrating as it approached the Sun, as it probably ran out of ice. The ESO Very Large Telescope has imaged the "shower" of "mini-comets" in Comet LINEAR on August 6, 2000. More than a dozen condensations are seen in Comet LINEAR, as "mini-comets" with tails. At the centre of each of them is a piece of the disintegrating cometary nucleus, perhaps some tens of metres across. Read the full text at ESO PR Photo 26/00.
Comet LINEAR (C/2001 A2)
Comet LINEAR was discovered on January 3, 2001, and designated by the International Astronomical Union (IAU) as C/2001 A2. Late March 2001, it was suddenly observed to brighten. Amateurs all over the world saw the comparatively faint comet reaching naked-eye magnitude and soon thereafter, observations with professional telescopes indicated the reason for this strange behaviour: the comet's "dirty snowball" nucleus had split into two pieces. When astronomers at ESO's Paranal Observatory turned the 8.2-m VLT MELIPAL telescope (UT3) towards that object in the evening of May 14, 2001, they noted that one of the two pieces of the nucleus appeared somewhat elongated: fragment "B" had split into two. Read the details in ESO PR Photo 18/01.