The Aspectual Strength of Planets, Drik Bala
Drik Bala is one of the important strengths in the Sixfold Strength Method or Shad Bala. Aspect is called in Sanskrit as Dhrishti. All planets aspect powerfully the 180th degree from their positions. The Aspect Angle, Dhrishti Kendra A planet cannot aspect any planet or House within 30 degree in front of it and 60 degrees behind it. In other words, a planet's aspect commences from 30 degrees and stops at the 300th degree its position.. So, a planet cannot cast his Dhrishti or aspect within 30 degrees and beyond 300 degress from its natal postion.
The Aspect Angle, Dhrishti Kendtra, commences from 30 degrees,
increases gradually and at 60 degrees it gets a value of 15 Shashtiamsas (
units of 60 ). This value increases till the Aspect Angle or Dhrishti Kendra
is 90. At 90 degrees, the value will be 45 Shashtiamsas. It decreases from 90
degrees and at 120 degrees, the Aspect Value or Dhrishti Value will be 30
Shashtiamsas. Again from 120 degrees to 150 degrees its Aspect Values goes
down and the Aspect Value will be Nil at 150 degrees. There is a quantum jump
from 150 degrees onwards till 180 degrees and the maximum Aspect Value of 60
Shashtiamsas will be attained at 180 degrees. This is what is called the
Seventh Aspect astrologically. ( All planets aspect the Seventh House from its
position ). Again the Aspect Value diminishes till it reaches 0 degrees at 300
degrees !
The Aspected Planet, Dhrusya Graha
The planet which is aspected by another planet is called Dhrusya Graha
The Aspecting Planet, Dhrishta Graha
The planet which aspects another planet or House is called the
Dhrishta Graha.

Equation for the Aspect Angle
If you subtract the longitude of the Aspecting Planet ( Dhrishta Graha ) from the longitude of the Aspected Planet ( Dhrusya Graha ) Aspect Angle, Dhrishti Kendra = Aspected body  Aspecting Body. The Aspect Value ( Dhrishti Value ) Subtract the longitude of thel Aspecting Planet ( Dhrishta Graha ) from the longitude of the Aspected Planet ( Dhrusya Graha ) and if the remainder is > 180 and < 300 degrees, subtract this reminder from 300 degrees and converting the remainder into minutes, divide the result by 7200, so that the Aspect Value may be calculated When the Aspect Angle is <180 and <300, subtract the Aspect Angle from 300 and divide the remainder by 120 degrees of 7200 minutes. In other words, if the Dhrishti Kendra is in between 180 and 300, the Aspect Value is equal to 300  Aspect Angle _______________  300  Aspect Angle ( D Kendra )
_________________________ * 60 (shashtiamsas ) 7200 120 So, 300  Aspect Angle ( D Kendra ) = Aspect Value ___________________________ 2
Mathematical Astrology appears a bit tough, but then the Sixfold Method is the best for evaluating the planetary strength.