Part 1: Method of Ptolemy
Each astrologer has one or a few methods for birth time rectification. These methods could either really work or be just to reassure the astrologer or the native about the of birth time. Whether its being practical or not, studying their mechanism reveals the thinking style of ancient astrologers.
There are some methods mentioned in Persian books and I am going to introduce those mentioned in a book named Rowzat al-Munajemin.
Rowza belongs to 11th century around 1073CE and is one of the reliable references in Persian. “Shahmardan” the writer states in the introduction that “Arabic books are not to be trusted and older Persian sources are not apprehensible so I write this book in contemporary Persian however its not my profession”. He was a philosopher and said he is not a professional astrologer but his phrase itself promises that he had access to a more original old resources have been used for material collection of his book. We will study more about him and his unique book later.
There are five methods of rectification mentioned in this book which are called “Nimudar”. These methods have been used in other sources as well and have been named after their original owners as following:
- Method of Ptolemy: This method looks at the new moon or the full moon before the birth and takes out the ascendant degree by using the degree of the most dignified Planet (Mubtaz) at that time.
- Method of Vettius Valens: This method measures the distance between moon and sun at sunset or sunrise and then indicates a variable called “Sun factor”. Then calculates another variable called “Ascendant factor” and then by using these two values, it takes out the rate of birth time difference.
- Indian method: This method calculates a mundane progression and then studies the lord of progressed time in the Dwads (Dodecatemoria).
- Method of Herms: This method calculates the conception time by the use of moon’s position.
- Method of Zoroaster: This technique uses the positive or negative events which have happened in native’s life, and then it finds out a fixed star or a planet responsible for that events then estimates the time by the progression of Hyleg or Kadkhudah (Alcocoden) or the ascendant.
This list itself shows the interaction between the Persian astrologers and astrologers of other sides of the world. Each of these techniques has a very specific foundation which gives some interesting Ideas about the way they were thinking. These are five different thought schools that have their own highlights. The logic behind the method of Zoroaster is closer to what contemporary astrologers do. Zoroaster technique uses the reverse calculations by taking the past events and figuring out their motives and causes but the other four put the time of birth in an equation of time and don’t pay any attention to the events of native’s life.
Method of Ptolemy:
The first method which is known as method of Ptolemy is known as “Animador” in west which has been taken from “Al-Nimudar”. Though Nimudar is a Persian term but the prefix ke the closer one to the assumedsidered., dantingg “Al” has been added in Arabic sources.
“this Ptolemy is not the author of Almagest”, Shahmardan states. It is mentioned in some other Persian books that this Ptolemy was a student of Herms not the author of Almagest. Also in Persian scripts, names of Ptolemy and Hermes mentioned a lot and many books are referred to these two. One the most well known ones is named “Samareh” which is famous for the commentary of Tusi which is referred as “Centiloquium” in west.
Shahmardan’s statement on Ptolemy’s technique is as follow:
“This technique is the easiest and the most precise amongst the other techniques and some people believe that this author is the same author of “Almagest” which is not true and Almagest’s author is a different Ptolemy who wrote the “Tetrabiblos”.
At first draw the mean chart with a time of +/- 30 minutes and extract the degrees of houses and planets at that time. Then find the previous new moon or full moon before the time of birth and find the Mubtaz or the most dignified planet.
The ascendant degree is equal to that planet’s degree.
If it was quite far away from the mean ascendant, we consider the degree of the 10th house equal to that planet.
Some astrologers make angular cusp which its degree is more closer to the degree of the dignified planet.
Some others take the angle aspected by that planet. for example, if it is in the 2nd house or the 6th house, they align the 4th house regarding those houses.
Never involve the sun or the moon as Mubtaz unless their degrees are precisely clear.”
In this technique we must consider the very previous new moon or full moon before the time of birth since the moon and the sun are two important pillars representing mother and father. Therefore, for a native to be born it should be a result of his mother and father’s relationship. The degree of the Mubtaz planet has a great impact on the birth of the native born during that fortnight. Though since this moon is the very previous new moon or the full moon before the birth of the native, the strongest planet can have great impacts over the native and its position gets so much importance as well.
Biruni states in his “Al-Tafhim” regarding this topic:
“If the time of birth hasn’t been noted down at the exact moment, then in fact there is no way to find out the right moment but astrologers have quite a few techniques to find out the degree of ascendant and then the closest time to the time of birth. Therefore, they use these indicators to take out a degree being used as the ascendant. Ptolemy’s indicator is more popular and it says” if the degree of the ascendant can not be found then another degree is obtained which is more important than the degree of ascendant.”
According to Biruni, the degree of that planet is considered as an important point in the birth indicator. He talks about recognition order of the angles same as Shahmardan does but he mentioned another point:
“Some astrologers set any angle which is closer equal to that planet.”
Since there is a big emphasis on choosing the right angle, it is obvious that a non-equal house system was being employed so the IC/MC axis should be considered.
This technique has been mentioned on Centiloquium at Stanza No.36 with an added phrase by Tusi:
“If the degree of the most dignified planet wasn’t absolutely as same as those founded, the degree of It’s partner (on which has less dignity) will be used.”
In this case according to Tusi we will have more than one degree which we can take the closer one.
The book is named “Rowzat al-Munajjemin” meaning “The garden of astrologers” which I will refer to Rowza for an easier pronunciation for westerners.
The author is “Shahmardan abi Khayr Razi” who will refer to him as Shahmardan
 Its 1/12th of a sign and called Dwadasamsa in Indian astrology
 Mubtaz has been called Almuten by mistake in some Latin scripts.