[Freeing the Mind][Self Development Contents]

# Ken Ward's Astrology Pages

## Astrology: Calculating the position of the planets.

Whereas the precise calculation of the house cusps requires a lot of detailed work, which is not really warranted from the accuracy of the birth data, the position of the planets can be easily calculated from tables.

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:

 Sun (Taurus) 7 May 1982 16:06:57 8 May 1982 17:04:59

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:

 Sun Position in Taurus Sun 7 may 1982 16:06:57 Sun 8 may 1982 17:04:59 Fraction 0.6375 Difference in arc 00:58:02 Proportion (0.6368 x 00:58:02) 00:37:00 sun pos 16:43:57

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:

 Planet Birth Position Sign 07 May 1982 08 May 1982 Factor Sun 16:43:57 ta 16:06:57 17:04:59 0.6368 Moon 12:16:49 vi 04:26:48 16:44:05 North Node 14:56:41 ca 15:03:08 14:53:01 Mercury 07:51:28 ge 07:10:01 08:15:02 Venus 03:28:47 ar 02:46:03 03:53:05 Mars 00:27:52 li R 00:31:05 00:26:02 Jupiter 03:59:34 sc R 04:04:04 03:57:01 Saturn 16:51:33 li, R 16:54:04 16:50:07 Uranus 03:17:11 sa, R 03:19:01 03:16:08 Neptune 26:39 sa, R 26:40:00 26:38:08 Pluto 24:57 li 24:58:03 25:56:08

Those with an R in the sign are retrograde planets.