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View Full Version : Basic Astrology #8; calculating the chart elements



Methanespirit
August 25th, 2001, 03:59 PM
Continuing with the chart calculations for 11/11/71 at 22:30 UT, or for our purposes the time is expressed as 22.5000 hrs. Most Astrologers use log-rhythms to determine the Zodiacal positions of the planets and luminaries in an Astrological chart. However, it is much quicker and simpler to use a 4-function calculator as demonstrated. The main idea in using the calculator is to find where the elements are located from their positions given between two dates by using percentages and applying that to thedaily movments. We will begin with the Solar position, both Tropical and Sidereal Zodiacs.

Sun's Tropical pos. 0 hrs UT on 11/11.........17* 55' 56" Sco.
sun's Tropical pos. 0 hrs UT on 11/12........18* 56' l6" Sco.
difference......................................................1* 00' 20"= 3620"

The daily motion , expressed in seconds of arc (3620"). Use the same type of ratio as in the RAMC example: 3620/24=X/22.5. X= 2293.75". Divide this by 60 = 56.5625'. Subtract the 56' and multiply the reminder by 60 = 34" rounded off. Now add the 56' 34" to the Solar position for 11/11: 17* 55' 56" + 56' 34" = 18* 52' 32" Tropical Scorpio. To change to the Sidereal Zodiac add the SVP value of 5 *39' 58" to the Tropical position: l8* 52' 32" + 5* 39' 58" = 24* 32' 28" Libra.

The Moon is a little more complicated in that most complete and accurate ephemerides list it's position twice daily. once at midnight UT and then again at Noon UT. This is because of it's rapid motion and that the orbit is elliptical, therefore, it seldom tavels at the apparent same speed between two 12-hour periods of the same day. Since our chart's UT is after noon on the 11th but before midnight the 12th., we must calculate the Moon's position between these two entries.

Tropical Moon position 11/11 at 12 noon UT .......6* 39' 56" Virgo
Tropical Moon position 11/12 at midnight UT......12*38' 58" Virgo
difference for 12 HOURS of motion......................5* 59' 02"

Next, take the 5* 59' 02" and convert this into seconds of arc: 5* x 60 = 300', add the 59'= 359' x 60 = 21540", then add the remaining 2 seconds = 21542". Since we are working with a 12-hour segment of the day, it is necessary to enter into the equasion the time being NO MORE than 12 hours. In this case, it is 22.5 - 12.000= 10.5 hrs. This, then becomes the multiplier of the Moon's motion: 21542"/12 = X/10.5. X=18849.75". Convert this back into degrees by dividing it by 3600 (3600 seconds per hour or degree) = 5.235902778. Subtract the 5 degrees and multiply the remainder by 60 = 14.154166. Subtract the 14' and multiply the remainder by 60 = 09". Now, add the total answer to the starting Lunar position of 6* 39' 56" + 5*14' 09" = 11* 54' 05" Tropical Virgo. Add the SVP value to the Tropical position to find the Sidereal: 11* 54' 05" + 5* 39' 58" = 17* 34' 03" Sidereal Leo.

Older ephemerides give the Lunar position once daily, and then sometimes only to the nearest minute of arc. To correct this approximation it is necessary to use calculus on a 4-function calculator, however, this will be included in a later study. (It isn't as complicated as it sounds!).