[I would have never made any progress in Jyotish, much less have written any articles, without the priceless tutelage of my Vedic Astrology guru Hart de Fouw. I thank him deeply.]
In the Beginning
Thousands of years ago, Vedic astrologers -- deeply spiritual and wishing to serve all who came to them -- were frequently approached by people who didn't know their birth time. In addition to creating the Whole Sign house system, which works even when charts are an hour off, Jyotishis knew that they could rely on the Chandra Lagna chart, also called the Chandra Kundali, to perform chart readings, because the Moon only changes sign every two-and-a-half days.
And since Indian children were named after the Nakshatra occupied by their Moon at birth, their Moon sign was known, and their Jyotishis could create a Chandra Lagna chart with ease. They just calculated when the Moon was in that Nakshatra on the birth date.
The Chandra Lagna chart is simply a birth chart rotated so that the Moon is located in the First House. (The practice of rotating charts to place specific points as the First House was used in both Jyotish and also in Hellenistic astrology, where they called the point placed as the Ascendant the Horoscopos.)
The reasons for the Moon being used as the Ascendant are simple:
1. The Moon is the fastest moving point besides the Rising Sign, and as such represents the individual well.
2. The Moon is revered in Indian culture, and in fact the Nakshatra it occupies is the basis for the foremost predictive system: Vimshottari Dasa.
3. The Moon also has the second greatest impact on life on Earth (after the Sun), and is the primary influencer of the tides.
In the above example, of Donald Trump's chart, you can see the birth chart on the left and the chart with the Moon is placed in the First House on the right, i.e. the Chandra Lagna chart.
[For beginners, the First House in the North Indian format charts is always the (shaded) diamond at the top center of the chart.]
The Uses of the Chandra Lagna Chart
The Chandra Lagna chart was used in five different ways:
1. As a Birth Chart. As aforementioned, since birth times (and even dates) in ancient times were uncertain, the Chandra Lagna chart was the perfect tool for giving accurate chart readings.
2. Reinforcement. Themes indicated in a person's accurate birth chart sometimes are also present in the Chandra Lagna, and if so, those themes are greatly reinforced and very likely to manifest.
A very important and frequently used example of this is if a yoga occurs both in the birth chart and the Chandra Lagna chart, then the yoga is much stronger.
3. Elaboration: The Chandra Lagna can show important qualities and events in a person's life that are not apparent in the birth chart. The Chandra Lagna can be a very valuable resource in this regard. Recently, for example, I saw one of my client's two careers shown in the birth chart and the other shown in the Chandra Lagna chart.
4. Transformations: The Chandra Lagna can reveal themes that actually occur in a person's life that one would not predict from examining the birth chart. I.e. if the two charts show contradictory results, one can benefic greatly by valuing both "windows" on the person's life.
5. Psychology: Many Jyotishis see the Chandra Lagna as indicative of a person's thoughts and feelings about their life, as well as indicating their degree of mental health. I have just begun to explore this approach.
There is a basic principle in Jyotish that the manifestation of the positive yogas in a person's chart relies on the strength of the Lagna. Therefore, a natural extension of this theme would be that the Moon must be strong and well placed in the Chandra Lagna chart if that chart is to reinforce the positive themes found in the regular birth chart or the Chandra Lagna chart.
Ascertaining Strength, Weakness, and Placement
What makes the Moon strong?:
Being Bright (within one sign of the Full Moon), in the 4th house, in its own sign or exalted (Cancer or Taurus) (in the birth chart and/or the Navamsha), being in its own Nakshatra, and/or being in a Parivartana yoga (sign swap) with another planet.
Weaknesses include: within 72 degrees of the Sun, waning (especially away from Full), in Scorpio (without a Neecha Bhanga yoga nor occupying an angle), or aspected by multiple malefics.
Good placement is in any house other than 6, 8, or 12.
Example: Donald Trump
If we look at Donald Trump's natal chart and Chandra Lagna chart (above) we see many of these principles at work.
Note: In Jyotish, a planet can be both strong and weak, and one does not nullify the other.
In his case, the Moon has strength because it's Full, as well as is in a Neecha Bhanga Raja Yoga (which gives it great power) because it is aspected by Mars, the ruler of Scorpio.
So the Chandra Lagna is strong enough to support yogas that occur in his chart.
1. As a Birth Chart. If we treat Trump's Chandra Lagna as the birth chart, we would guess that the person is very assertive, if not aggressive, due to a strong (Dig Bala) Mars aspecting its own Ascendant, which is certainly very true.
We would also expect a strong career and popularity for the same reason, which has proven the case.
2. Reinforcement. Two different themes are strongly corroborated in the Chandra Lagna chart: his powerful libido (called a Passion Combination in Jyotish), and his "Manas disorder", i.e. his tendency to "blow a fuse" when he gets too upset.
3. Elaboration: While there are reasons why we would see Trump as a successful person, his success is significantly more evident when looking at his Chandra Lagna.
In his Chandra Lagna chart, he has the best Raja Yoga possible: the strong lord of the 9th (the Moon) opposite the lord of the 10th (the Sun) ensuring major successes and prominence in his life. This shows just how valuable Chandra Lagna analysis can be.
4. Transformation: In his birth chart, we see financial gains, in that Mercury -- in its own sign and not aspected by malefics -- is the lord of both money houses (2nd and 11th) and he also has a strong Jupiter in the 2nd.
However, the truth of Trump's financial life is that it has been marked by major ups and downs. This pattern is clearly shown in his Chandra Lagna chart due to the placement of the 11th lord in the 8th house. So the Chandra Lagna chart helps us to understand his financial themes more accurately than just his birth chart.
5. Psychology. As mentioned in #2 above, Donald Trump has instability wired into his physiology and psychology. This is very clearly elucidated in the Chandra Lagna chart because the Moon itself is eclipsed by Ketu.
Example: Barack Obama
I decided to add one more example, just to focus on the idea of "reinforced yogas".
As you might remember, for a positive yoga to be significant in a person's life, at least one of the yoga-forming planets must have strength. (And the converse is true too: negative yoga-forming planets should be notably weak.)
When we look at Obama's birth chart, we see what I call a "Spiritual Raja Yoga", i.e. the rulers of two trines (fire houses) in mutual relationship: a doubly strong Saturn as lord of the First House opposite Mercury, Lord of the Ninth House. This gives Obama many blessings, a strong sense of Dharma, and enhances his life considerably.
And yes, in his Chandra Lagna chart, the same two planets rule Dharma houses again: Saturn rules the Ninth House and Mercury rules the Fifth House, thereby forming a Spiritual Raja Yoga again. No wonder he became president!
[Note: Politics is indicated by the Ninth House and both yogas involve the lord of the Ninth House.]