Astrology is a combination of art and science that studies the location of planets and the symbolic meaning associated with it to determine their influence on the human lives. Its existence dates back to thousand years when it was documented in writing by the ancient astronomers and astrologers. The natal astrological chart gives the full picture of position of stars during time and location of your birth. You may get the astrological readings in the newspapers, televisions or Internet daily but that is very cursory and makes only a part of the natal chart. The natal chart assesses you in terms of you strengths and weaknesses that allow you to clog the holes in you personality.
Before we go into the discussion how birth time influences astrological readings, let us dismantle some myths associated with astrology. It, as many think is a religion, is not so. It is also not Satanism or black magic. It is not associated with any physical energy that radiates out of the planet. It studies the symbolic meaning of the location of the planets at the time of your birth and determines the influence such a planetary position can have on your life. It doesn't foretell any event. It only predicts a possibility of an event. Two people born at the same time and place will not have same astrological reading. It allows you to make the appropriate use of your qualities to live up to the best of your capacities.
The birth time is not only used to find out the positions of the planets but also your Ascendant (Rising Sign). That calculation then determines the midheaven and the house cusps. The house cusp in astrology is like a circle divided into 12 sections. Each section is called a house. The line that demarcates two houses is a cusp. The ascendant is the cusp of the first house. The house cusp is calculated by converting your birth time into sidereal time for the latitude of the birth place. The midheaven is the cusp of the tenth house of the natal chart. The midheaven and the house cusp tell about our career, relationships, life path, and social standing and reputation.
An inaccurate birth time will produce erroneous reading in astrology. Therefore have your birth certificate before getting your natal chart made. Sometime the time in birth certificate is also not accurate. Doctors generally round off time like 6:37 to 6:40 or 6:35. Some people do not have birth certificates at all as they were born at home or in hospitals in those days when birth certificates were not considered essential.
An erroneous birth time can be rectified as well. Rectification is a long process in astrology that includes backward forecasting in your life and fine-tuning the time until it corresponds with all the important past events of your life. It is a costly investment. But if you have a good memory to remember all significant events in your life and have a birth certificate that records an approximate birth time, the time and investment could be less.