# Page:Simplified scientific astrology - a complete textbook on the art of erecting a horoscope, with philosophic encyclopedia and tables of planetary hours (IA simplifiedscient00heiniala).pdf/58

CHAPTER V.

HOW TO CALCULATE THE POSITIONS
OF THE PLANETS

As the Ephemeris is caleulated for Greenwich at the time when the Observatory clock strikes twelve. it is necessary to make corrections for other hours and for places East or West from that point when it is desired to calculate a horoscope.

By adding four minutes for each degree of longitude the birthplace is West of Greenwich to the true local time of birth we obtain the Greenwich Mean Time as recorded by the Observatory clock. This is written G. M. T.

We will apply this rule to calculate the G. M. T. of the horoscope for August 2, 8:15 A. M. at Chicago, which is 88 degrees West longitude:

 H. M. True Local Time of Birth (see page 38) 8 23 A. M. Aug. 2 4 min, times 88 degrees equal 352 min. 5 52 Greenwich Mean Time (G. M. T.) 2 15 P. M. Aug, 2

Multiplying the degree of West longitude of Chicago (8% degrees) by four minutes gives us 352 minutes, which we divide by 60 because there are 60 