Aryabhatt Vedic Lessions
Nature of Planets
Analysis of a horoscopic chartrequires a thorough understanding of the nature of planets. It is on the basis of a proper knowledge of the nature of planets that good and bad results can be predicted with any accuracy. Before venturing into predictive aspect of astrology, it is imperative on the part of a practitioner of astrology to spend some time mastering the principles that govern the benevolence and malevolence of planets.

Planets may be benefic or malefic by nature. Or they become benefic or malefic depending uopn the nature of the rising sign in a horoscope. Benefic and malefic planets produce their results when their appropriate dashas operate. Dashas thus help us in the timing of events.

The nature of various planets is determined on the basis of standard astrological principles mentioned by the classical writers.

The following account is primarily a reproduction of the same principles.
Malefics and Benefics by nature
Planets may be malefic or benefic depending upon their inherent nature. Thus, Jupiter, Venus, waxing Moon and well-associated Mercury are natural benefics. Similarly, the Sun, Mars, Saturn, Rahu and Ketu, waning Moon and afflicted Mercury are natural malefics. The Moon though a mild and benevolent planet, behaves as a malefic when too close to the Sun. Mercury gets influenced too easily; it thus behaves as a benefic under benefic influence and as a malefic under malefic influence. Rahu and Ketu too can behave as benefics especially when placed in the signs of Jupiter and Mercury.
Benefics and Malefics for different Lagnas
Parashara's Principles
Planets behave as benefics and malefics depending on the houses they own. The ownership would naturally vary from one lagna to the other. In other words, for a give lagna, certain planets will behave as a benefics while others will behave as malefics or neutrals. This will be independant of their inherent nature. Planets thus are subservient to the lagna. On the basis of the principles discussed hereunder, a natural benefic may assume the role of a malefic while a natural malefic may assume a benefic role.
Principles - Part I

(a) Natural benefics as lords of quadrants (houses 1,4, 7 and 10) shed their beneficence.

(b) Natural malefics as lords of quadrants shed their malefics nature.

(1) Natural benefics are the Moon, Mercury, Jupiter and Venus; natural malefics are the Sun, Mars, Saturn, Rahu and Ketu.

(2) Lordship of quadrants has a neutralising influence on the nature of planets. The natural benefics thus lose the capacity to give benefic results, while the natural malefics lose their capacity to do harm.

(3)Only the ownership of quadrants does not convert benefics into malefics, and vice versa.

(c) Lords of trines (houses 1, 5 and 9) give benefic results no matter whether by their inherent nature they are benefics or malefics.

Note : Lord of the lagna is both the lord of a quadrant and a trine. it is thus supposed to give benefic results irrespective of it's inherent nature.

(d) Lords of the third, the sixth and the eleventh houses are always malefic.

(e) Lords of the second, the eighth and the twelfth houses behave as neutrals. They give results according to their location as well as association.

Note : Lords of the 2nd, 8th and 12th houses are impressionable neutrals.

Principles - Part II
The twelve houses in a horoscope have been divided into four groups above : (a) the quadrants; (b) the trines; (c) the 3, 6, 11 group; and (d) the 2, 8,12 group. In each group the relative strength of the various house lords is described thus

(a) Of the lords of the quadrants, the 4th lord is more powerful than the lagna lord; the 7th lord is more powerful than the 4th lord; and the 10th lord is more powerful than the 7th lord.

(b) Of the trine lords, the 5th lord is more powerful than the lagna lord, while the 9th lord is more powerful than the 5th lord.

(c) Of the 3, 6, 11 group, the sixth lord is more powerful than the 3rd lord while the 11th lord is more so than the 6th lord.

(d) Of the 2, 8, 12 group, the 12th lord is more powerful than the 2nd, while the 8th lord is more so than the 12th.
Principles - Part III
The lord of the 8th house, though considered a neutral, has a special propensity to do evil. The eighth house represents obstructions, obstacles, failures, intrigues, ailments, death and the like. The following points must be remembered while considering the 8th house.

(a) Eighth house is the 12th from 9th (indicating loss of Bhagya); hence its lord ie ever malefic.

Note :
(i) 12th house from lagna indicates loss. 12th house from any house indicates loss of that house. Since the 9th house stands for Bhagya (luck), virtues, pious deeds, religious inclinations, father, etc., the 12th from it (i.e., the 8th) indicates the loss of all these. Loss of fortune or luck is considered the biggest loss.

(ii) When the 8th lord is also lagna lord, the benefic nature of the lagna lordship prevails, and the 8th lord tends to behave as a benefic unless it is particularly afflicted or ill placed.

(b) The 8th lord is still more malefic when it also lords over the 3rd or the 11th house.

Note :
(i) For Pisces ascendant, Venus is the lord of the third and the 8th houses and is bad.

(ii) For Virgo ascendant, Mars is the lord of the third and the eighth houses and, therefore, adverse.

(iii) For Taurus ascendant, Jupiter is the lord of the 8th and the 11th houses, and is adverse.

(iv) For Scorpio ascendant, Mercury as the lord of the 8th and the 11th houses is bad

(c) The eighth lord becomes a benefic when it also owns a trine.

Note :
(i) Jupiter and Mercury for Leo and Aquarius ascendants respectively own the 5th and 8th houses, and behave as benefics.

(ii) For Gemini ascendant, Saturn as the lord of the 8th house as well as the 9th house (a trine) does not become an outright benefic, and, according to the Bhavartha Ratnakara, gives mixed results only.

(d) The evil effects of the 8th house lordship do not apply to the Sun or the Moon.

Note : The Moon is the 8th lord for Sagttarius ascendant, and the Sun for Capricorn ascendant. According to the sage Parashara, the Sun and the Moon remain un-afflicted by the 8th house lordship. This, however, may not hold true in actual practice, at least in medical astrology.
Principles - Part IV
(a) When a planet owns both a quadrant and a trine, it becomes particularly useful and is called a Raja-yoga-karaka (doer of great benefit). It gives additional benefit if it is also located in a quadrant or a trine.

Note :
(i) Mars for Cancer and Leo ascendants, Venus for Capricorn and Aquarius ascendants, and Saturn for Taurus and Libra ascendants, become Yoga-karakas because of the ownership of a trine and a quadrant.

(ii) Some people doubt the efficacy of Saturn as a benefic for Taurus ascendant despite its ownership of the 9th and the 10th houses (a trine and a quadrant respectively). This is because the 9th lord is considered a Badhaka (an obstructing agent) for a fixed lagna like Taurus. This , however, is not the view of Parashara which is more authentic.

(b) Only the ownership of a quadrant does not convert a malefic into a benefic. The malefic must also own a trine to completely shed its malevolence.

Note : Saturn, as the lord of the 10th and the 11th houses for Aries ascendant, as lord of the 3rd and the 4th houses for Scorpio ascendant, and as the lord of the 6th and the 7th houses for Leo ascendant, remains a malefic despite owning a quadrant in each case.

(c) The blemish of kendra lordship (ownership of quadrants), as applicable to benefics, increases progressively from the Moon, to Mercury, to Jupiter, to Venus.

(d) Full Moon, Mercury, Jupiter and Venus, in this order, are progressively more powerful as benefics.

(e) Waning Moon, the Sun, Saturn and Mars, in this order, are progressively more powerful as malefics.
Principles - Part V (Raja Yogas)

When the lord of a quadrant is in some way related to the lord of a trine, a Raja Yoga (or a highly benefic combination) is formed. Benefic combinations in a horoscope neutralise affliction and are good for remaining free from disease. Relationship between any two house lords can be in one of the following ways :

(a) By location in the same house (conjunction).

(b) By mutual aspect.

(c) By an exchange of houses (Parivartana Yoga).

(d) When one of them is placed in the other's house and this latter aspects the former.

Note : When the lords of quadrants and trines are related in one of the ways indicated above, they still do not produce a Raja yoga if they also own the Papasthanas (adverse houses), i.e., houses 3, 6 and 11.

Principles - Part VI (Rahu and Ketu)

(a) Rahu and Ketu give results according to the house where they are located, and according to the planet (i.e., the lord of a house) whom they join.

(b)Rahu and Ketu become Yogakarakas (productive of Raja Yoga) in the following situations :

(i) When they are placed in a quadrant, and join a trine lord; or

(ii) When they are placed in a trine, and join a quadrant lord.

(c) Rahu also behaves as Saturn and Ketu also as Mars.
Trik Houses and their Lords
Houses 6, 8 and 12 are known as Trik houses. While these houses, their lords, as well as the planets that associate with these houses and their lords are productive of adverse results, they are particularly adverse in relation to health. The sixth house and the sixth lord, among other things, indicate disease and accidents. The eighth house and the eighth lord indicate chronic disease, incurable disease, or death. The twelfth house and its lord indicate suffering and also hospitalisation. The dasha periods of the planets associated with these houses and their lords must be carefully watched for determining illness.