“Astronomers from the Jet Propulsion Laboratory and the U.S. Naval Observatory have solved the ancient mystery of the origin of the Chinese calendar, it was reported to the 182nd meeting of the American Astronomical Society today in Berkeley, Calif. Kevin Pang of JPL and John Bangert of the Naval Observatory said they have found a date in 1953 B.C. when the sun, moon and five planets all lined up in the sky at dawn — providing the basis for the beginning of the Chinese calendar.
Pang said this was all the hint he and Bangert needed. A computer search of planetary positions in the 2000 B.C. era gave only one possible match — March 5, 1953 B.C.
Before dawn on that day, Mercury, Venus, Mars, Jupiter and Saturn lined up like a pearl necklace in the eastern sky, next to the Great Pegasus Square, he said. The planets all spanned but a few degrees. The new moon occurred shortly thereafter when the sun, moon, and five planets all lined up in Pegasus, exactly as Liu had stated. The dawn of March 5, 1953 B.C. was indeed the beginning of a day, month, year and all known planetary cycles, the magic moment …. “ – https://solarsystem.nasa.gov/news/133/astronomers-solve-ancient-mystery-of-the-chinese-calendar/
“The third and final factor involves the number of planets in conjunction at one time. By increasing the number of planets, the frequency of events will decreases sharply. For example, the interval between the time when Mercury, Venus, Mars, Jupiter and Saturn are easily visible in close proximity span from March 3, 1953 BC to September 8, 2040 AD (table 3.2).. Even the close alignment of four bright planets are quite rare (from June 1564 to Feb 2378).
Table 3.2: Grand Planetary Conjunction of 2040 A.D.
Year Date UT Mag. Mag. Sep
2040 Aug 18 01:49 1.7 Mar-Jup -1.7 35′
2040 Aug 31 01:31 1.7 Mar-Sat 0.9 110′
2040 Sep 01 17:39 -3.9 Ven-Jup -1.7 10′
2040 Sep 06 17:56 -3.9 Ven-Sat 0.9 88′
2040 Sep 07 21:03 -0.2 Mer-Jup -1.7 88′
2040 Sep 11 12:09 -0.1 Mer-Sat 0.9 185′
2040 Sep 13 04:04 -3.9 Ven-Mar 1.7 13′
2040 Sep 20 15:43 -0.0 Mer-Mar 1.6 139′
Table 3.2 shows the conjunction pairs associated with the Grand Conjunction of 2040. Although this event occurs over a one month period, only around September 6-8 will the planets be most favorably aligned.” – http://climate.gi.alaska.edu/Curtis/astro5.html
I would gravitate toward notion that when Mercury, Venus, Mars, Jupiter and Saturn lined up as a pearl necklace ( 五星連珠 ), during this time, the Chinese Astronomers started keeping track of the flying stars ( 玄空飛星 ) period ( 元運 ). With the limitation in technology, the accuracy of the measurement is questionable. And, whether or not later practitioners have calibrate the Feng Shui ( 風水 ) application with planetary alignment.
Time period is divided into 20-Year cycles. Each cycle of 20 years is a Period. In this model, a grand cycle comprises 9 periods ( 三元九運 ) in total, which covers a span of 180 years. Periods are used to describe the cyclical pattern of Qi ( 氣 ); different types of Qi ( 氣 ) have its own specialty or area of focus relative to that particular Period.
Period Years Elements Trigrams
1 1864–1883 Water Kan North Water
2 1884–1903 Earth Kun Southwest Land
3 1904–1923 Wood Zhen East Thunder
4 1924–1943 Wood Xun Southeast Wind
5 1944–1963 Earth – Center –
6 1964–1983 Metal Qian Northwest Heaven
7 1984–2003 Metal Dui West Lake
8 2004–2023 Earth Gen Northeast Mountain
9 2024–2043 Fire Li South Fire
In astronomy, the great conjunction refers to the planetary alignment of Jupiter and Saturn. The last great conjunction took place on May 31, 2000, next is in December 2020. This planetary alignment of Jupiter and Saturn take place every 19.85 years. This approx. 20 years duration has close similarities with the flying stars theory of marking out a new period. This is one reasons to believe that the changes of period in flying stars theory that originally developed; had came from observation of planetary alignment.
Put in perspective, In a grand cycle of 9 periods ( 三元九運 ) totaling 180 years. There would be a deviation of 1.35 years. To put across bluntly, if commencement of the periods in the flying star system is based on planetary alignment. After many grand cycle of 9 periods ( 三元九運 ) , the overall deviation could be significant. And, most of the flying stars practitioners would likely be using an incorrect period to plot the Feng Shui ( 風水 ) chart of a house. By following the planetary alignment, period 9 should be in 2020 instead of the commercially said 2024. And after 30 August 2040, it would be a start of a grand cycle, period 1. The year 2020 庚子 also coincide with 5 period luck cycle (河圖五運) commonly use in Purple White Script (紫白訣).