A rare astronomical event will be visible in Hong Kong today as the planet Venus comes between the sun and the Earth, to appear as a black dot against the sun. The transit of Venus across the face of the sun last occurred 122 years ago in December, 1882. The next one is not expected until eight years from now in June, 2012. Between 1.12pm and 7.19pm, the silhouette of Venus will move across the sun's disc. As the sun is due to set at 7.09pm today, the sight should be visible in Hong Kong for most of the six hours, if smog levels and weather co-operate. According to the Hong Kong Observatory, the best places to observe the transit will be those with an unobstructed view of the west, such as Pokfulam, Stanley, Lamma Island, Cheung Chau and Tai O. People are warned, however, not to look directly at the sun with the naked eye or through a telescope, and to avoid observing the transit for a prolonged period of time. 'A safe method of viewing the transit is to do so by projecting the sun's image onto a piece of white paper or cardboard to view the reflection,' an observatory spokesman said. Various activities have been organised in the territory to celebrate the phenomenon. The observatory and the Hong Kong Space Museum are hosting a live webcast of the event between 1pm and 6pm. Images taken by the Space Museum will be updated by the minute. The Hong Kong Astronomical Society has organised a gathering at the Ho Koon Nature Education Centre in Tsuen Wan, for teachers and students to view the transit and learn about the phenomenon. Society president Leung Kam-cheung said about 70 people had registered from various schools, including teachers, students and some parents. A webcast will be used to capture images and project them onto a large screen for students to view as well. A small telescope will be set up with a solar screen to reduce the impact of the sunlight and make for safer viewing. Further information can be obtained from the observatory website at www.hko.gov.hk . Heavenly visions Best time to view the Venus Transit 1.12pm to 7.09pm (sunset) Best places West-facing spots in Pokfulam, Stanley, Lamma Island, Cheung Chau and Tai O On the web www.hko.gov.hk/gts/event/venus_transit/webcast_e.htm , www.hk.space.museum and www.weather.gov.hk/gts/event/venus_transit/webcast_e.htm