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A comet designated as C/2012 S1 (ISON) will approach the Sun in late November this year, reaching perihelion on November 28 when it will be very close to the Earth. If weather permits, people in Hong Kong will be able to see this rare astronomical phenomenon.
Comet ISON was discovered in September 2012, when it was still beyond the orbit of Jupiter, by two astronomers participating in the Russian International Scientific Optical Network (ISON). As the comet is a "sungrazer" (i.e. its perihelion would take it much closer to the Sun than ordinary comets) that was spotted at such a large distance, astronomers initially predicted that, by the time of perihelion on November 28 this year, the brightness of Comet ISON would reach a magnitude of -5, surpassing the brightness of Venus and creating a long and magnificent tail across the sky.
However, as the distance of Comet ISON from the Sun shortens, its brightening has turned out to be much slower than expected. To date, while it is about 0.5 AU (the average Earth-Sun distance, about 150 million kilometres) away from the Sun, its brightness has only reached a magnitude of about 5. According to the latest assessment, Comet ISON will still be visible, if weather permits, through a pair of binoculars in Hong Kong, low in the dawn sky to the east in late November before it passes perihelion and in early December after it has made the passage.
The Curator of the Hong Kong Space Museum, Mr Chan Ki-hung, noted that people may try to observe the comet during the dawn at sites with an unobstructed view to the east such as Shek O and Clear Water Bay. However, there are still uncertainties at the moment concerning how bright the comet will be or whether the comet can survive its flyby of the Sun.
Mr Chan added, "As the comet will be very close to the Sun, it is not suitable to conduct any observation after sunrise because the bright sunlight will not only make it difficult to observe the comet, but will also cause severe damage to the eyes if viewed directly."
Those interested in the comet may visit the website at www.isoncampaign.org/ for the latest updates. Please refer to the latest "7-day Weather Forecast" issued by the Hong Kong Observatory at www.weather.gov.hk/wxinfo/currwx/fnd.htm for the weather and www.hko.gov.hk/gts/astron2013/almanac2013_index_e.htm for the time of sunrise.
Ends/Monday, November 18, 2013
Issued at HKT 18:16
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