In Sanskrit this is also called the “Prashna Kundali” or the “Question Chart”. Many people do not know their exact birth details or accurate birth details.
In such cases the astrologer then takes recourse to what is known as the question chart. The question chart is nothing but a similar chart as described above except in this case, the date and time and place, signifies the date and time and place when and from where the question is asked.
The planet positions and ascendant are all computed based on standard astronomical observations and calculations. As per Vedic astrology or Jyotish, the natal horoscope chart contains the basic signatures in a person's life, which is the basis of analysis for the astrologer and his/her astrology forecasts.
Similarly the question chart also contains the signatures, which often clearly indicates the success and failure of a particular question that the person asks. Of course, if the astrologer can analyze both the natal chart as well as question chart, then his astrology predictions are more accurate and reliable.
How does an astrologer analyze is not the topic for this article, which I may take up at some other time. As a simplistic overview, each zodiac sign has a planet as its ruler, which is fixed and same for all charts. Sun and Moon rule Leo and Cancer respectively. Mars rules Aries and Scorpio. Mercury rules Gemini and Virgo. Jupiter rules Sagittarius and Pisces.
Venus rules Taurus and Libra. Saturn rules Capricorn and Aquarius.
There can be more than one planet in a particular zodiac sign in the birth chart, which naturally depends on the date and time of birth.
Each house in the chart signifies different aspects of our life. Each planet has its best and worst sign, friendly sign and unfriendly sign in the chart, which is true for any chart. Similarly there are good houses and bad houses in the chart. For example ascendant or first house is good house, but 8th house is a bad house for any chart.
How the planets are situated in the house and sign are the main principles on which a natal chart is analyzed or for that matter any chart is analyzed..
The Derived astrology charts and reports:
The natal horoscope chart is the basic chart from which a whole lot of other charts are computed based on precise mathematical procedures and formulae.
An astrologer needs to consult those other charts also to make accurate astrological predictions.
A comprehensive list of horoscope charts are given below.