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Ken Ward's Astrology Pages

Astrology: Calculating the position of the planets.

Let's remind ourselves of the example being used:

Example: Mary was born  7 May 1982 at 11 hours 17 minutes AM, New Berlin, New York, USA. The longitude is 75 degrees, 20 minutes west of Greenwich. And the latitude is 42 degrees 37 minutes North of the equator. Her LST is 1 hour 16 minutes 13 seconds. GMT birth time: 15:18:20

While we needed the local sidereal time to calculate the position of the house cusps, we need the GMT time of birth to calculate the positions of the planets.

In our example, we collect the following information from an ephemeris. I am using a midnight ephemeris, which gives the planet positions at the beginning of each day (at midnight) as opposed to a noon ephemeris, which gives the positions of the planets at noon each day. From the ephemeris I extract this data:

As Mary was born at 15 hours 17 minutes UT then the actual position of her sun will be calculated using this as a fraction of 24 hours. This fraction is approximately 15.2833/24 or 0.6368 (I will leave the number as it is, without rounding up.

We therefore get, with the midnight ephemeris:

The sun is, therefore, in 16 ta 44, rounding up to minutes. In a similar manner we can calculate the positions of the rest of the planets:

Those with an R in the sign are retrograde planets.