Solar arc force behind the thought origin early, but always beside the point, and calculation of trival, so there is no universally applied.Mature solar arc force behind the method is to forming of the 20th century, the accuracy is guaranteed, since the sun arc push is gradually widely used.

Continuous improvement has a long history

The original astronomy, calendar, and astrology originated in two river basin, the people think that the circumference of the 1 degree and time of 1 day there are internal relations: because the circumference of a total of 360 degrees, and about 360 days a year, so every day the sun about 1 degree forward into the background of stars.

In the second century AD, Ptolemy slam the door "on behalf of 1 degree 1 day" concept, put forward "on behalf of 1 degree 1 year" technology.Specifically, after the birth of transit along the ecliptic to move 1 degree (about 3.9890 minutes) map corresponding to the fortunes of 1 year that is to say, about 4 minutes after the birth of the map represents the fortunes of 0 and 1 years old, eight minutes chart represents 1 to 2 years old.

Ptolemy the disadvantages of this method is: planetary motion is too slow, according to his method, 2 hours after the birth of the condition of the corresponding to the fortunes of 30 years after the birth of six hours and the corresponding 90 fortunes, but most of the planet in a force behind the map is almost no movement.This method theory is accurate, is very complicated to operate, and it is of practical significance for the basic have no conclusion.

Ptolemy this push method of transport was called "the main limit method" (Primary Direction).

In the late 16th and early 17th century, scholars Antonius Maginus further Ptolemy's theory, put forward the method of "time limit" (the Second Progression), with corresponding 1 year "1 day" instead of "1" corresponds to 1 year.

Another contemporary scholars Valentin Naboth running distance of 1 day the sun comes down to a mean: 59 minutes and 8 seconds.Due to the simple, easy to operate, this method is very popular.

According to legend in the 17th century, Kepler has developed a shipping method.His method is said to be like this: a case in the birth chart the sun and the degree of a planet is poor, is he (she) in events associated with the planet's age.

Famous 17 th-century stargazer William leary had three force behind the feeling prevue current method (Ptolemy, Maginus version, Naboth version), but not too good.But Maginus help Naboth published books ever appreciated Naboth version of the delivery method, considered the most accurate.

The end of the 19th century, British scholar Sepharial (his real name is w. g. Old) method development a step forward, will push again on the basis of Naboth daily average line speed, will one day the sun degree directly add on all the other planets, to represent 1 year.

Eliminate the error so perfect

When you are in practice, however, to paraphrase Naboth method when the shipment will be found that age, more than 30 years later, when the case that the time will often for a year or two earlier, age difference, the more people born especially in summer.

The reason for this is that does not take into account changes in the velocity of the the sun in a year.In short, the method of 1 degree represents one year doesn't work well in practice, the average 1 day on behalf of Naboth, 1 years practice effect is slightly better, but are often inaccurate.

One year, the sun is fast or slow: fastest in winter, summer is the slowest.If a person was born in the summer, if with Naboth daily average line speed instead of the practical running distance, within one day the sun every day (every year) will have a little error, 30 years later about this error will be accumulated to 1 degree, thus caused the claim time ahead of the actual event occurs, the map view, 30, 31 to actually happen will happen.

Into the 20th century, along with the gradually birth records, astrology's emphasis on birth chart than the emphasis on divination.In the UK in the early 20th century scholars, astrologers Aaron Leo (Alan Leo) writings, has more importance to push the delivery time limit.The limitation of the time limit of a force behind the basic motionless, lies in the outer planets within all claims are based on the sun and planets, and the meaning of this a few within the planet is limited.

Main limit, time limit and small amount of information, people need to better use of shipping method, so the arc method finally timely complete the shipment.

Naboth force behind the cumulative error problems until the 20th century, but what exactly is who has not got.

Eventually proved to use solar arc force behind the law is summed up in two steps:

1. 1 day on behalf of 1 year after birth.

Within one day (2) the degree of the sun, directly added to all the other planets and sensitive (note the north-south intersection is also moving forward, the sun's arc push shipment no retrograde).

Such a force behind the map can bring birth chart and see.(The zodiac /astro/)

Later, the halfway point of the Hamburg school theory was introduced to the sun's arc push shipment, proved very useful.