Rule Of Rotation - Sao Văn Khúc

Vietnamese astronomers perceived that within the heavens, there are two sets of objects moved above the earth. First, the stars of the night sky were conceived of as a dome that rotated clockwise over the earth on an axis defined by the pole star (sao Tử Vi). Second, the sun (Thái Dương) and the moon (Thái Âm) and the five visible planets (Ngũ Hành Tinh) were believed to move counterclockwise over the earth, contrary to the motion of the stars, but also around the axis of the circumpolar region. The movement of the dome stars was measured by reference to directions on the face of the earth. The movement of the sun, moon, and the planets were traced agianst the backdrop of the dome of stars. Both the surface of the earth and the dome of the stars were divided into 12 equal parts (12 cung Tử Vi trong lá số )

To grasp this understanding of the heavens, picture the solar system as a two-dimensional image viewed from above the earth north pole. Consider only the sun, the moon and the 5 visible planets. Mercury (Thủy Tinh), Venus (Kim Tinh), Mars (Hỏa Tinh), Saturn (Thổ Tinh), Jupiter (Mộc Tinh) are traced counterclockwise orbit around the earth. Earth rotates counterclockwise around its own axis. Next, imagine the visible stars as a sphere surrounding the solar system. This dome remains still as the planets orbit the sun the the moon orbits the earth. The earth imaginary axis defines the North Star (sao Tử Vi) roughtly at the center of the northern hemisphere of stars. Although for the Tử Vi astronomers, this was more than just an axis. It was the axis that defines cung Sửu and cung Mùi, where the sun and the moon meets (Thái Dương & Thái Âm đồng cung).

Since the earth orbits the sun in the same direction as other 5 planets, the sun appears to move counterclockwise around the earth against the background of the steller dome. Due to the earth's daily counterclockwise rotation around its axis and yearly counterclockwise orbit around the sun, the dome of the stars appears to revolve around the pole star in the clockwise motion.

As the astronomers observe, they discovere that at midnight (giờ Tý), during the new moon (first day of the month), the moon lies between the earth and the sun (Thái Dương & Thái Âm đồng cung tại cung Sửu) and in the month of the winter solstice (ngày đông chí), the handle of the big dipper pointed to the branch Tý direction due North. In each succeeding two hour period, the handle of the dipper point to each of the corresponding directions, which is the branch Sửu.

With that rule of nightly rotation, we can clearly see that the our ancient Tử Vi astronomers had created the rule of the stars Văn khúc, 1 of the stars in the Big Dipper, to start at the branch Thìn due to the winter solstice move clockwise every 2 hours.

Sao Văn Khúc - từ cung Thìn kể là giờ Tý, tính thuận đến giờ sinh an sao Văn Khúc.

Hi LinhNhi,

Very interesting post! There are couple points I'd like to clarify (assuming this is your work).

Due to the earth's daily counterclockwise rotation around its axis and yearly counterclockwise orbit around the sun, the dome of the stars appears to revolve around the pole star in the clockwise motion.

The above sentence also apply to other stars around star Tu Vi, meaning they are all revolve clockwise around the pole star. So if we define clockwise is forward then all stars move forward in 12 palace in TuVi Method ?

Does this:

To grasp this understanding of the heavens, picture the solar system as a two-dimensional image viewed from above the earth north pole

or

Both the surface of the earth and the dome of the stars were divided into 12 equal parts (12 cung Tử Vi trong lá số )

define the 12 palaces ? I have a hard time visualize the two dimensional plane. The first one seems to indicate the equatorial plane or at least the celestial plane while the second seems to indicate horizontal plane.

It was the axis that defines cung Sửu and cung Mùi, where the sun and the moon meets (Thái Dương & Thái Âm đồng cung).

Is it true that the sun and the moon meet at Suu or Mui palace ?

PTS

PTS,

Due to the earth's daily counterclockwise rotation around its axis and yearly counterclockwise orbit around the sun, the dome of stars appears to revolve around the pole star in the clockwise motion. Since the earth revolves 360 degree counterclockwise around its axis, the dome stars appears to rotate 360 degrees clockwise each day. However, each day the earth also progresses ~1 degree in its 360 degree daily rotation , so the dome stars actually appears to rotate ~361 degree daily. Consequently, over the course of years, the additional of roughly one degree each day brings the dome of stars back to its original position at the end of each year.

As for the sun and the moon appears at the section Suu and Mui can be explained as the the position of the moon against the background of the stars can be directly observed most nights. The position of the sun among the stars can not be directly observed but must be extrapolated. By extrapolated, we are able to know when the sun and the moon were in the same position in relation to the dome of the stars. In Tu Vi, this is refered the the new moon as a convergence of the sun and the moon. Since the sun and the moon appear to converge relatively in the same 12 points against the dome of stars each year, it was possible to divide the dome into 12 equal sections, by the 12 earthly branches. These 12 zodiacal signs indicate the section of the sky where the sun and the moon converge. This is not the same as the 12 western zodiacal constellations. When referring to the constellations of the stars, Tu Vi employed a system of 28 lunar lodges (nhị thập bát tú).

The 12 sections of Tu Vi is used to describe the 12 directions on the earth's surface. Section Tý corresponds to due north, branch Mao due east, and so on... Using these methodology, ancient astronomers discovered that in the Ty' hour or midnight on the 1st day of the lunar month in the winter solstice, the handle of the Big Dipper pointed exactly in between the section Ty', while the sun and the moon located in the section Suu.

In each succeding 2 hours, the dipper handle would point to each of the corresponding. directions, while the convergences of the sun and the moon move counterclockwise through the 12 zodiacal signs. After that, at midnight on the first day of the following month, the handle of the Big Dipper pointed to a opposite direction, clockwise motion. This is later referred in Tu Vi as "Nhị Hợp" or "Nguyệt Kiến"

The year was origininal believed to begin at the point of least sunlight during the winter solstice and to culminate with the peak of the sun's strenght at the summer solstice. This is the key rule for the Southern Hemisphere. In the nothern hemisphere at the winter solstice, the southern hemisphere would be the summer solstice. That's mean when the big dipper pointed in the section Ty, the southern dipper would be pointing in the section Ngo.

So when winter solstice, the sun rises at the section Thin and set at Tuat. The rule for the star "Văn Xương" which is one of the star in the southern dipper in the summer solstice which mean starting at the section "Tuat".

Rule for star "Văn Xương": bắt đầu từ cung tuất là giờ Tý , tính nghịch đến giờ sinh là cung của sao Văn Xương.

PTS,

I hope this will explain why the rule for the star "Văn Khúc" and sao "Van Xương" do contracting each other. The northern dipper, 'sao Văn Khúc" start from section Thìn, while the southern dipper, "star Van Xương" starts from section "Tuat". One rotate clockwise and the other rotates counter-clockwise

LinhNhi

Linh Nhi,

Thank you for a detailed explanation!

After that, at midnight on the first day of the following month, the handle of the Big Dipper pointed to a opposite direction, clockwise motion. This is later referred in Tu Vi as "Nhị Hợp" or "Nguyệt Kiến"

At the moment I cannot visualize this, but it is an interesting thought or observation.

There are some things for us to think about.

1. As you said

These 12 zodiacal signs indicate the section of the sky where the sun and the moon converge. This is not the same as the 12 western zodiacal constellations. When referring to the constellations of the stars, Tu Vi employed a system of 28 lunar lodges (nhị thập bát tú).

I thought of this as Thien Ban where the 12 parts are fixed and addressed by the 28 constellations (correct me if I am wrong). Therefore the observation that Suu Mui are the only two points of new moon (sun meets moon) is NOT always true. However, it may be true in the horizon system which I thought of it as Dia Ban. These two systems are completely different.

2.

So when winter solstice, the sun rises at the section Thin and set at Tuat. The rule for the star "Văn Xương" which is one of the star in the southern dipper in the summer solstice which mean starting at the section "Tuat".

Is this rule will be true for all cases ? I would think not. Through out the year the rise and set locations of the sun varies as observed from one location to another.

I hope this will explain why the rule for the star "Văn Khúc" and sao "Van Xương" do contracting each other. The northern dipper, 'sao Văn Khúc" start from section Thìn, while the southern dipper, "star Van Xương" starts from section "Tuat". One rotate clockwise and the other rotates counter-clockwise

Yes so northern atmosphere stars always moves in the opposite direction to those in the southern's

I thought of this as Thien Ban where the 12 parts are fixed and addressed by the 28 constellations (correct me if I am wrong). Therefore the observation that Suu Mui are the only two points of new moon (sun meets moon) is NOT always true. However, it may be true in the horizon system which I thought of it as Dia Ban. These two systems are completely different.

If the 12 sections of Tu Vi are based on the section of the sky where the sun and the moon converge, then the lunar new year begin in the month of the Tiger. If the 12 sections in Tu Vi was to be determine by the constellation, then 5000 years ago, the first month of the year would be the month of the Rat, and 5000 years later, the first month of the year would be the month of the Cat or the Dragon.

Is this rule will be true for all cases ? I would think not. Through out the year the rise and set locations of the sun varies as observed from one location to another.

The position of the sunrise shifts along the horizon over the course of a year. The position of sunset also shifts by the same amount. java script:;How far this migration of the sunrise or sunset extends along the horizon depends on where you live. At the equator, the sunrise position migrates plus or minus 23.5° from due East, while at Minneapolis, which is located 45°N latitude, the position can vary about plus or minus 35° from due East. In contrast, the rising and setting positions of stars don't change over the course of a year, but the rising and setting times do change.

Therefore, if we based our 12 sections of TuVi based on the where the sun and the moon converge, the rule of the star rotation doesn't change based on the location of birth. It is a little confussing, but it does make sense.

That's why sometime the Sun rises ahead of the star. Then in a couple of month, the star is lost in the glow of sunrise. Finally, the star is visible ahead of the sunrise, and we have our marker for the calendar.

LinhNhi

Very interesting post! There are couple points I'd like to clarify (assuming this is your work).

PTS,

This idea LinhNhi got from the book "Tu Vi Thien Van Hoc" written by an admired member of vietlyso and this forum. It has been written but has not and never be published.

LinhNhi

If the 12 sections of TuVi are based on the 12 zodiac constellation, then the people living in the southern hemisphere can't apply the current rule of TuVi star arrangement. In the other hand, using the sun as guildance, the sun will always rise East North (cung Dan) in the summer. In the winter, the sun will will always rise East South (cung Thin) in the Winter. This is true for all people living the Northern or Southern Hemisphere.

I think what for ever reason that caused the author of "Tu Vi Thien Van Hoc" decide not to publish his "idea" was helping him. Because his idea was NOT COMPLETE if not saying wrong. Instead of addressing each of the statements you made individually, I like to share with you the image I just made. This image will give ideas of whether or not TuVi can be applied to southern hemisphere (haha I get it right this time. I kept typing atmosphere for hemisphere, thank you for not picking on it like other people).

From my perspective, I think if TuVi used the 12 palaces divided by the constellations it would be more unified.

For the first image, it will provide information on different people at different points on earth see stars at different location at different time in the year. The second image and third provide information on location of the sun on the 12 palaces on a horizon system for people at different location on earth. Keep in mine that some people do no see the sun for couple months, the last two images also show that.

Hopefully this image can provide more information with the hope that I understand it correctly. Nevertheless I like to thank you for get my brain to exercise.

PS. Just realized that the stars G and F I put in the middle of the circle (intersection between ecliptic and equator) are missing.

PTS,

There is a big different between the 12 sections of Tu Vi and the rule of rotation among the stars in the 12 constellations

LinhNhi

LinhNhi,

I was hoping you can give me the basic formation of the so called Tu Vi 12 sections.

PTS

PTS,

In astrology, the zodiac denotes those signs that divide the ecliptic into twelve equal zones of celestial longitude. As such, the zodiac is a celestial coordinate system, to be more precise, an ecliptic coordinate system, taking the ecliptic as the origin of latitude, and the position of the sun at vernal equinox as the origin of longitude.

One should not be confused the 12 sections of the zodiac to the 12 constellations of the zodiac. The path of 12 constellations of the zodiac is the path of the celestial equator. The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator.

I still do not have a clear view of your definition of "12 sections of TuVi", so does the 12 Sections of Tuvi the same as 12 sections of the zodiac ? if not then how was the 12 sections of Tuvi formed ? I'd like to get this straight before continue (if you want to).

PTS,

The 12 sections of Tu Vi and the 12 sections of western zodiac has many similarity and some differences.

The 12 sections of Western Zodiac is divided based on the whole sign house system, sometimes referred to as the 'Sign-House system', the houses are 30° each. The ascendant designates the rising sign, and the first house begins at zero degrees of the zodiac sign in which the ascendant falls, regardless of how early or late in that sign the ascendant is. The next sign after the ascending sign then becomes the 2nd house, the sign after that the 3rd house, and so on. In other words, each house is wholly filled by one sign

The 12 sections of Tu Vi is divided based on the equal house system the ecliptic. It is also divided into twelve divisions of 30 degrees, although the houses are measured out in 30 degree increments starting from the degree of the ascendant. It begins with the ascendant, which acts as the 'cusp' or starting point of the 1st house, then the second house begins exactly 30 degrees later in zodiacal order, then the third house begins exactly 30 degrees later in zodiacal order from the 2nd house, and so on. The Houses are numbered counter-clockwise from the position of the eastern horizon (the cusp of the first house, "Cung Dan") at the time of the subject being charted. Houses one through six are below the horizon, while houses seven through twelve are above the horizon.

The distinction between whole sign houses (Western Zodiac) and equal houses (Tu Vi) lies in the fact that in whole sign houses the cusp of the 1st house is the beginning of the sign that contains the ascendant, while in equal houses the degree of the ascendant is itself the cusp of the 1st house. And the 1st house start at the intersection between the circle of ecliptic and the celestial equator, which is the spring equinox, cung Dan

LinhNhi,

ps: Whenever I have more free time, I will go into more details how the 12 sections were divided into "Tam Hop" or the division of the 12 sections into 3 quadrants: angular, succedent and cadent. And what does it means when the star lies within these 3 quadrants.

LinhNhi,

Ok, There are three basic systems that ly hoc dong phuong knows about, that are the horizon system, the ecliptic system and the equatorial system. As far as I know ly hoc dong phuong (or as least the Chinese text indicate so) only use the horizon system and the equatorial system. The horizon plane uses the horizontal coordinate system which is azimuth and altitude where as the ecliptic and equatorial system both use celestial coordinate system which is longitude and latitude. So just to avoid confusions when we say celestial coordinates, let call it ecliptic coordinates equatorial coordinates. and Leaving that aside....

I misunderstood you when you wrote "The 12 sections of Tu Vi is used to describe the 12 directions on the earth's surface. Section Tý corresponds to due north, branch Mao due east, and so on... Using these methodology, ancient astronomers discovered that in the Ty' hour or midnight on the 1st day of the lunar month in the winter solstice, the handle of the Big Dipper pointed exactly in between the section Ty', while the sun and the moon located in the section Suu.". It really means that the Tuvi divides its 12 sections on the horizontal plane. Now I understand that you said the 12 sections divide on the ecliptic plane when you said "The 12 sections of Tu Vi is divided based on the equal house system the ecliptic" which is contradict with Chinese text that I have read and also English text. I also think you are contradicting yourself when you said "One should not be confused the 12 sections of the zodiac to the 12 constellations of the zodiac. The path of 12 constellations of the zodiac is the path of the celestial equator. The celestial equator is a great circle on the imaginary celestial sphere, in the same plane as the Earth's equator.

". But that is beside the point.

Now, given what you said that the Tuvi 12 sections are on the ecliptic plane, using ecliptic coordinate system. I would assumes that any person on earth is affected by the stars only if they can see them (this was why the ancient used horizon system because they saw and observed the stars). It does make sense because if you cannot see the stars its energy cannot get to you (assuming you don't put any reflective object to redirect the energy). Also, alot of the stars used in Tuvi method are at the North pole, therefor most areas in the south pole (of the earth) won't be able to see those stars. You can see that in my drawing. Clearly that Tuvi method was invented by people in the northern hemisphere and therefore Tuvi method may not fully applicable to people in the southern hemisphere.

PTS

ps. I think you should cite the images.

PTS,

Try to imagine the world in 3 Dimensional

LinhNhi,

What is the purpose for the imagination and what aspect should be focused ? Your response is usually very open that I do not know its purpose.

By the way, looking at your image, my first two questions are 1. How were Tý and Ngọ determined ? and 2. The ancient really knew about the plane in red ?