Free Astrology Lessons: What is a Natal Chart? Natal Chart is a map of the planets and zodiac signs

Free Astrology Lessons: The Natal Chart is a map of where the planets are when a project begins.

The project is "imprinted" with the astrological influences at the moment it begins. A natal chart for a person is done for the moment a person is born.

Two things are needed from a person (or event) to calculate the birth chart: the time and place of the birth. 

Generally people know their date of birth, but the time may have to be obtained from hospital records, a baby book, or government records. 

Without the birth time, a partial astrological analysis can be done, but a precise birth time is needed for a complete astrological analysis. For the great majority of astrological work, the town or city is required. 
wiki Free Astrology Lessons What is a Natal Chart

The country or county is not sufficiently accurate for a complete analysis. On the other hand, the precise hospital or street the person was born on is generally not required; the town or city of birth is sufficient.

What is a Natal Chart From the time and place of birth the natal chart can be calculated. The very first step in calculating the birth chart is to determine the latitude and longitude of the place, and also the time zone and whether daylight savings time was observed. 

The latitude and longitude of birth can usually be easily obtained from an atlas. However, the time zone and daylight savings time present a formidable problem! 
Observance of daylight savings time is extremely complicated during some time periods in some countries

Many astrologers have found that written records (hospital records, government records, baby book) are accurate more often than the memory of people present at the birth, including the mother. 

Probably the second most important cause of inaccuracies in chart calculations is incorrect daylight savings time information, and sometimes also incorrect time zone information. 

Free Astrology Lessons To calculate a chart manually, then, a person needs an ephemeris, a table of houses, an atlas or other reference book that gives the latitude and longitude of cities, and a book that has daylight savings time and time zone information. 

There are many books written especially for astrologers that include the latitude and longitude, time zone, and daylight savings time information together in one book.