Guide to celestial phenomena in December: Gemini meteor shower and civil engineering

December has entered the winter, although the weather is cold, the sky theater is wonderful. In addition to mercury, the other four visible planets can be observed this month. Although Venus is closer to the sun, December has shorter days and longer nights, making it easier to appreciate it in the morning. Although Mars has passed the big impact, it is about 20 o’clock, which is just the time of mid day on Mars, and the observation conditions are good. Saturn and Jupiter are closest in angular distance this month, and they can be seen every day after work. On the 21st, we recommend that we focus on the “civil engineering convergence” which has been in place for 20 years. In terms of meteor shower, the Gemini meteor shower, which is the end of the year, has a great impact on moonless nights, which makes people have the impulse to observe all night. In addition, the little bear meteor shower is also worth monitoring. < p > < p > on December 13, we can see the moon covering Venus in the Kamchatka Peninsula, and other regions can see the Venus with very close angular distance. It is October 29 of the lunar calendar, and we can see the very thin crescent. Take Beijing as an example, the Venus rises at 5:25, the brightness is – 3.8, the moon rises at 5:35, and the sun rises at 7:28. Since the rising time of the sun is two hours shorter than that of Venus and the moon, we can see that the stars gradually disappear around the bright moon and the stars, and the dark background gradually turns to the yellow red color before sunrise. The sky is very suitable for viewing, but we need to get up early. The Gemini meteor shower, as the end of the year’s astronomical phenomena, will not disappoint us in general. In particular, December 14 this year is October 30 of the lunar calendar. There is no interference of moonlight all night. The observation conditions are very good, which is very suitable for public observation. The parent of Gemini meteor shower is an asteroid, not a comet. It is the second known meteor shower not caused by a comet. The Gemini meteor shower is active from December 4 to 17 every year. This year, the maximum meteor shower occurs at 8:50 Beijing time on the 14th. The peak hourly zenith flow is estimated to be about 150. The whole night of the 13th and the whole night of the 14th are good observation time without the interference of moonlight. After watching Saturn and Jupiter, the radiant point of Gemini meteor shower is already above the horizon. Here to remind readers, the best angle to watch the meteor shower is not to stare at radiation points, meteors may appear in various positions. The characteristic of the meteors in the group is that their backward extended line points near the radiation point, and their velocity is close to each other. There will be a total solar eclipse in the Southern Hemisphere from 13:33 to 17:54 UTC on December 14, 2020. The total duration of the eclipse is more than 4 hours, but the total solar eclipse passes through only a limited area in Chile and Argentina, and most of the eclipse zones fall in the South Pacific and South Atlantic Ocean. Fortunately, the maximum eclipse point is located on the mainland, located in Negro Province, Argentina. The maximum eclipse time is 2 minutes and 9 seconds. The total solar eclipse is far away from China. It is not recommended to go so far away. On average, “civil engineering convergence” occurs once every 19.6 years. Civil engineering, which is very close to each other, has a proper term in English, called great conjunction. However, there is no such term in Chinese, so we can call it “civil conjunction” for the time being. The last time Saturn and Jupiter were so close was on May 28, 2000, but that year, because Jupiter and Saturn were close to the angle of the sun, people did not have a chance to enjoy it. This “civil conjunction” occurred on December 21 this year. The conditions are good, and can be observed in a period of time after sunset. The angular distance between Saturn and Jupiter will reach about 7.0 minutes. Saturn and Jupiter move slowly across the celestial sphere and are easy to find by looking southwest after sunset every day throughout December. During this time, Jupiter is the brightest star in the southwest sky in the evening, and the slightly darker star next to it is Saturn. If we enjoy it in the telescope, we will have a chance to see a picture of both of them in the same frame as their satellites. < p > < p > the active period of the little bear meteor shower is from December 17 to 26 every year, and the maximum occurs at 17:00 on December 22, Beijing time, and the zHR is about 10. The small bear meteor shower will occasionally break out, and the zHR can reach about 50. In the past 70 years, there have been few observational records of the little bear meteor shower, including two eruptions in 1945 and 1986. Between 2006 and 2008, there were reports of a slight increase in its traffic. Since the radiant point of the little bear meteor shower reaches 76 ° declination, for Chinese fans, almost all the meteors in the little bear meteor shower will not be missed, and can be observed all night. However, compared with the Gemini meteor shower this month, the flow of the little bear meteor shower is too small. In the cold winter, it is not recommended to watch the “iron powder”.