[ Lesson 1 ] [ Lesson 2 ] [ Lesson 3 ] [ Lesson 4 ] [ Lesson 5 ] [ Lesson 6 ]

JYOTISH LESSONS
Best viewed with Times CE Sanskrit Fonts

Download PDF

ASTRONOMICAL CALCULATIONS IN JYOTISH

4.1. The Time of Birth 

Astrology is the science that examines the quality of time, while astronomy is the science that calculates the quantity of passing time. For purposes of an astrological reading we utilize certain tools of astronomy, with the help of which we are able to calculate the position of planets and other significant points of the chart at the time of birth, etc.  

After all, in Jyotish we are always interested in the position of the planets at the time of a certain event. This is true for all branches of Jyotish. In natal astrology (Jataka) we are interested where the planets were transiting at the time of the native’s birth, as this is the most determinant time point in his life. In horary astrology (Prashna) we are interested in the transit of the planets at the time of the native’s putting his question to the astrologer. In Dasa analysis we are interested in the transit of planets at the time of dasa-pravesa (setting in of a period). In Tajaka astrology we are interested in the transit of the planets at the time of the native’s birth day. In Gochara (transit analysis) we are interested in the transit of the planets at the time of a certain event. This is also the point of interest in Electional Astrology (Muhurtha).  

Therefore the astrologer should be able to ascertain the position of the planets within the zodiac at a certain given point in time. Let’s take as an example the time of birth for Rabindranath Tagore (May 7, 1861, 4.02 am LMT, Kolkata). The exact time of birth is usually taken as the time when the umbilical cord is cut, although there are some other opinions as well, but at this time the body of the child is completely separated from the body of the mother. 

4.2. Local and Zonal Time 

Time is a phenomenon which is inseparable from space. Therefore besides ascertaining the time of birth, we also need to know its location, because at the same point in time (if it is independent of location, it is called Universal Time) the planets and the ascendant are situated differently above different parts of the globe, although their mutual disposition is the same.

 Local time is calculated according to the movements of the Sun. The Sun needs exactly one day to make a circle around the globe of the earth (at least apparently, if we look at it from the point of view of the earth), and this means that there will be a certain point in time every day when the Sun will exactly cross the longitudinal meridian of a certain nativity. This time is called local noon. The time interval between two points of local noon is exactly one day, which is divided into 60 ghatikas in Jyotish. One ghatika thus equals 24 minutes of the western calendar. So astronomically the time of an event may be identified by saying how much time has passed since local noon at that meridian. Since the Earth is divided into 360 longitudinal meridians, the Sun traverses over one degree within 1/6^th of a ghatika, which is four minutes. Therefore local times at different longitudes are different by four minutes each.  

Tagore was born in Kolkata, which is at 88 degrees 22 minutes of arc to the East of Greenwich. Let’s say if we take a city which lies at 80 degrees 22 min east, local noon will occur 8*4=32 minutes later than in Kolkata, because the Sun travels from East to West. This measurement of time, although very exact astronomically, may create problems when more distant places develop communication with each other. Thus with the setting in of the telecommunication era at the beginning of the 20th century, it was decided that the countries of the world would be divided into time zones, within which the time would be identical. This means that most of the smaller countries are situated within one time zone, and therefore the zonal time is identical in the whole country.  

The zonal time is actually the local time of a certain meridian within the zone, which is extended to the whole of it. For example in the whole of England, and part of Western Europe the zonal time is identical with the local time in Greenwich, which is assigned to be at the zero degree longitudinal meridian. The local time at 15° east from Greenwich is 1 hrs more than there, because the Sun crosses that place earlier. So in modern times the watches usually go by the zonal time, and therefore we also need to know the time zone of the nativity, plus in some countries one or two hours are added as summer time. After ascertaining which point in local time (or universal time) corresponds to the reported birth time, we may proceed to the calculation of the position of the planets.  Local time is usually indicated as LMT (Local Mean Time). Other time zones also have their abbreviations, like GMT (Greenwich Mean Time), CET (Central European Time), IST (Indian Standard Time) etc.  

4.3. Divisions of Time 

An interesting question  is how did the ancients measure the passing of time? As we have stated the relationship between time and space is inseparable, therefore they have measured it with the help of the motion of the planets, especially the Sun. There are still several Sun-dials existing in different parts of India, exact up to the second. This method however is limited to the time when the Sun is up and visible in the skies. Undoubtedly, many people are born during the night, so we also need to have a way to measure time when the Sun is not visible. This is where the word “ghati” comes from. It means an earthen pot of a certain size with a spout of a certain diameter. When the pot was filled with water, it took exactly 24 minutes for the water to flow out of it. One ghati is also divided into 60 vighatis, and one vighati into 60 palas.  

4.4. Determining Planetary Positions 

After finding out the time and place, the next task is to determine the position of the planets. This can be done in several ways: 

1.     By applying certain astronomical equations.

2.     By making astronomical observations.

3.     By using an ephemeris (Panchanga) with pre-calculated planetary positions.

 It is said that in the Rig Veda one can find certain mantras, which translate into astronomical equations, with the help of which, the planetary positions for any moment in time may be calculated. However these rules are quite obscure nowadays.

Astronomical observations are made regularly in different parts of the globe, and the information serves as a basis for calculating the ephemeris positions for the planets. These tables of ephemeris are available both in India and the West. If it is a western astrology ephemeris, you need to know the exact ayanamsha value, with which the tropical zodiac is shifted from the sidereal one.

The ephemeris usually gives the exact positions of the planets for certain points of time (daily, weekly, monthly etc.) which means that in the majority of the cases we need to know how far is the point of birth from the closest time indicated in the ephemeris, and after calculating the difference, we should also calculate how much do the different planets move within this time.

All of the above methods are combined in the different Jyotish software available, which usually give exact planetary position for any specified time. Therefore nowadays this is the most popular tool used for astronomical calculations.  

4.5. Movements of the planets 

Vedic astrology deals with seven grahas, i.e. Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn. Besides that the lunar nodes, i.e. Rahu and Ketu also occupy an important role. They are called shadowy planets, or chaya-grahas. The trans-Saturnian planets are not taken into consideration when erecting a Vedic chart. This is not because the ancients were unfamiliar with the rest of the planets, but rather because these seven visible planets and the lunar nodes represent the whole spectrum of energies, similarly to the seven colors of the rainbow, plus ultraviolet and infrared, which would represent all the colors of the spectrum. Therefore adding new heavenly bodies will not enhance the system of predictions extrapolated by the ancient Maharishis. However in Jyotish another set of planets appears, which is called upagrahas. These secondary planets will be explained in a later issue.  

The planets move within the belt of the zodiac with a different average of speed. The two luminaries, i.e. the Sun and the Moon have steady and direct motion, which means from Aries to Taurus to Gemini, etc. Therefore when any planet moves in the opposite direction to the luminaries, that motion is called vakra, or retrograde. The luminaries move with the same angular speed at all times. For the Sun it takes one year to complete a circle, while for the Moon it’s one month. As the Lagna (ascendant, which actually signifies the Earth) completes one circle of the zodiac within one day, these three will from the tripod of life (Lagna-body; Moon-mind; Sun-soul) and determine by their movements the three basic units of time (a day, a month and a year). 

On the other hand, the lunar nodes, Rahu and Ketu always move in retrograde direction, also with a regular angular speed. The nodes need 18 2/3 years to complete one circle of the zodiac and they stay one and a half year in every sign. The luminaries are said to be the two eyes of Lord Vishnu with which He maintains and oversees His creation, always upholding dharma and leading people on the path of righteousness. The nodes, however are the separated body and head of a demon called Rahu, who rebelled against dharma. Thus the nodes will represent karmic reactions which are the result of not following dharma and performing sinful activities. Therefore they are always against progress, although Ketu may be considered a benefic towards dharma, because after all the role of karma is also to teach us where we went wrong, thus encouraging detachment from sinful life. 

The rest of the planets, i.e. Mars, Mercury, Jupiter, Venus and Saturn most of the time move in the direct way, but at times they fall into a retrograde cycle. Their movement is not regular, which means that at different angular distances from the Moon they move at a different speed. This resembles human beings, who most of the time try to follow dharma, although their endeavour is not steady, but at times they fall under the influence of adharma, and thus they perform sinful activities and block their own advancements. Thus while the luminaries represent deva-gana or godly beings, Rahu and Ketu represent rakshasa-gana or demons, the rest of the planets will represent manushya-gana or human beings.  

Mercury and Venus are inner planets, i.e. they revolve around the Sun and pass between the Sun and Earth. Thus they revolve around the zodiac in the company of the Sun, and therefore the greatest angular distance of Mercury from the Sun is 27°, while for Venus, it is 47°.  

The following table represents the average daily angular motion of the planets, the approximate time they spend in one sign and the approximate time they need to complete a full circle in the zodiac. The symbols in the brackets indicate the direction of their movement.

4.6. Retrograde planets 

As we have said, retrograde motion indicates the destructive and obstructive forces of karma. Therefore, if any planets are retrograde in the chart, we may expect that a strong desire is connected to that planet. The planet’s power increases when it is retrograde or stationary (state of planet just before and after retrogression), but the results get delayed, become disturbed. After ascertaining what role does the given planet play in the chart, we may understand that the native has some unresolved problems or unfulfilled duties in that area, coming from previous life. Every planet gets retrograde when it is at a certain degree from the Sun. Before retrogression occurs, the planet gets stationary for a certain period of time. At this time the planet gives a very strong and steady effect. The same thing occurs when the planet ends its retrograde cycle. The following table shows the degrees and durations of retrograde and stationary motions:

4.7. Combustion 

Combustion occurs when the planets get too close to the Sun. The Sun is the strongest planet and its rays burn up the rays of the other planets. However the lunar nodes do not get combust, but rather they will eclipse the Sun and the Moon if they get closer than 5° to the luminaries. If at the same time the Sun and the Moon  are conjunct or in opposition (i.e. at the time of new Moon or full Moon), then the nodes eclipse both the luminaries. At the time of new moon even a visible solar eclipse could occur, as well as at the time of full moon a visible lunar eclipse. Birth during eclipses is considered to be inauspicious, and proper remedial measures should be undertaken. At the same time, when the Moon gets closer than 12° to the Sun, especially on the last day of decreasing Moon, krishna-caturdasi, it also becomes very inauspicious, and remedial measures should be performed. 

The rest of the planets become combust when they get closer to the Sun than a certain orb. When they are exactly conjunct with the Sun, then the Sun completely burns up their rays, and thus they are unable to function. In this case the areas lorded and influenced by the combust planet become inactive. They will bear very meagre results, and the native will experience strong oppression from some superior force in certain areas of his life. The degree of combustion depends on the proximity of the combust planet. However we should note that the planets will get combust only when they approach the Sun during direct motion, because in this case they pass behind the Sun, while during retrograde motion they pass in front of the Sun. Thus the phenomenon of combustion does not occur, rather the planet gains more strength from the Sun. The only exception is Venus, which revolves in the opposite direction, thus it will get combust while retrograde, and will not get so while direct.  

The degrees of combustion for the different planets are the following:

4.8. Planetary war 

Planetary war (graha yuddha) occurs when two planets come closer than one degree to each other in longitude. We should note that only the five above mentioned planets may get into a graha yuddha. The Sun will burn off any planets getting close to him. The Moon is very friendly, so she will avoid fight. The nodes are so subtle that they cannot be caught. However, they tend to eclipse and thus negatively influence any planet with which they get into close conjunction. 

Of the two planets, the following will win the war: 

1.     One which passes to the north of the other (which has higher latitude),

2.     One which has a more favourable appearance, brightness and steadiness,

3.     One which has bigger size,

4.     One which is direct and more distant from the Sun,

5.     One which has more strength from other sources.

The effect of planetary war is significantly different from that of combustion. While during combustion the Sun suppresses the influence of the combust planet, at the time of planetary war, the winning planet takes over the influences of the loser. This is like in a war the winner takes over the land, people, treasures, animals etc. of the loser and exercises control over them. So the winner will act as the lord of the houses lorded by the loser, and occupy its natural karakatwas also.* 

The following is the Rasi chart of Rabindranath Tagore, computed by the Jagannath Hora v 7.02 software of SJC (The divisional charts will be discussed in a later issues, therefore they are not displayed here):

 Assignments: 

1.Find out, whether there is any retrogression, combustion, planetary war etc. in the chart and what effects are being produced.
2.     Find out from the chart, what is the Moon phase and what will be its effect.
3.     Find out whether any planets are stationary at the time of birth of the nativity.
4.     What would be Tagore’s birth time given in IST (Indian Standard Time, GMT+5h30m)?

  © Gauranga Das