According to astronomical science experts, this year's first Mercury elongation will be staged on January 12, when as long as the weather is fine, at dawn about a week before and after the elongation, interested members of the public can look low in the east and observe the closest planet to the sun with the naked eye or with the help of binoculars.
Among the planets in the solar system, the orbits of Mercury and Venus are both on the inner side of the earth, which are intraterrestrial planets, and the large elongation is a phenomenon unique to intraterrestrial planets.
Lai Dihui, a member of the Chinese Astronomical Society and a director of the Tianjin Astronomical Society, said that the so-called large elongation refers to the maximum angle of the planet from the sun from the earth. For Mercury, this is between 18 and 28 degrees; For Venus, it is between 45 and 48 degrees.
The large distance is divided into the east distance and the west distance. The planets within the earth are called elongations to the east of the Sun and elongations to the west of the Sun. At the eastern elongation, the inner planets appear in the low western sky at dusk; At the greatest western elongation, the planets appear low in the east at dawn. Around the time of the great elongation occurrence, it is a good time to see the planets within the earth.
The angular distance between Venus and the Sun is much greater than that of Mercury and the Sun, and Venus is very bright, so the observation conditions of Venus at the time of the great elongation are significantly better than those of Mercury. Lai Dihui said.
During a conjunction cycle, the planets within the Earth will have an eastern elongation and a western elongation once. The conjunction period of Mercury is about 116 days, Venus is about 584 days, and there will be 6 to 7 Mercury major elongations per year, and Venus may not have a single major elongation for a whole year.
This is the surface of Mercury photographed by the American Messenger Mercury probe. (Xinhua News Agency, AFP).
Mercury has no distinct atmosphere, so it lacks a protective layer, is heavily eroded by the solar wind, and its surface is full of impact craters and canyons, among which the Carolis Basin is one of the largest craters in the solar system. Lai Dihui said.
Mercury will have a total of 7 major elongations in 2024, and this time on the 12th will be the first and one largest western elongation. Mercury magnitude 03rd class, the horizon height is 15 degrees, and the observation conditions are good.
September 22, 2023, Mercury's greatest western elongation. This is Mercury photographed by Han Ling, a starry sky photography enthusiast in Guangdong, in Zhongshan, Guangdong Province on September 24. (Photo courtesy of me).
How to find Mercury? With the bright planet Venus as a reference or guide, it will be easier to find Mercury. "Venus has been appearing in the eastern sky as the 'morning star' since late August 2023, and Mercury is not far to the lower left of Venus during this western elongation. Of course, Mercury can be observed not only on the day of the major elongation, but can be observed with the naked eye or with the help of binoculars for about a week before and after the major elongation. Lai Dihui said.
Curator: Liu Xinhui.
Reporter: Zhou Runjian.
Poster: Hu Yanzhu.
Editors: Chong Dahai, Zhu Shun.
Jointly produced by Xinhua News Agency and Xinhua News Agency Tianjin Branch.
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