On the 30th, a great distance between the east of Venus will occur to welcome the good opportunity to observe the "Chang Gung Star."

Tianjin, 28 Oct (Xinhua) -- According to astronomical science experts, on October 30, the eastern distance of Venus will occur, and at that time, the brightness of Venus will be about -4.6 and so on. With binoculars or small astronomical telescopes, interested members of the public can also enjoy the enchanting figure of Venus like a small moon.

Venus is the close neighbor of the earth, which was called "too white" in ancient China. When it appears in the morning, people call it "daystar" or "morning star"; when it appears at dusk, people call it "Chang Gung Star" or "Evening Star". Typically, Venus is the brightest object of the day except the Sun and Moon, with a maximum brightness of -4.9 magnitudes.

Song Yuanyuan, director of the Tianjin Astronomical Society and an expert in astronomy science at the Tianjin Science and Technology Museum, said that in most cases, Venus is very bright when observed on the earth, and the brightness exceeds -4. Because it is somewhat farther away from the Sun than Mercury, it will be easier to observe. The so-called east (or west) distance of Venus refers to the fact that Venus is on the east (or west) side of the Sun, and from the Earth, Venus has the largest opening angle with the Sun.

Venus' orbital period is about 225 days, and the rendezvous period with Earth is about 584 days, so the interval between the two adjacent west or east distances is about 19 months. The time interval between Venus from the west to the east is long, about 440 days, while the distance from the east to the west is short, only about 140 days. This results in a minimum of 0 and a maximum of 2 venus large distances per year.

Also the inner planet, Mercury is more common. Mercury has an orbital period of about 88 days and a rendezvous period with Earth of about 116 days. Each rendezvous period occurs once in the east and one large distance in the west, so there will be 6 Mercury macros in most years and 7 in very few years.

Since the end of March this year, Venus has begun to change from "morning star" to "evening star", and since then, the angular distance from the sun has been increasing, and it is easy to find its traces in the low western sky after sunset in July, which perfectly interprets the title of "Chang Gung Star". From August to December, Venus will be brighter than magnitude -4.

"During this period of great distance, the angular distance between Venus and the sun can reach 47 degrees, the horizon height at sunset is about 17 degrees, the brightness is about -4.6, and the southwest sky shines like a bright lamp, which is very recognizable." For the next two months or so, as long as the weather is clear and every day after sunset, people can observe Venus. Interested members of the public who observe Venus for several consecutive days through binoculars or small astronomical telescopes can clearly see that the shape of Venus is the same as that of the Moon, and there are changes in circles, sometimes like curved hooks, sometimes like semicircles. Song Yuanyuan said. (End)