The English Era + 3102 gives the Kali Era, the Era of the Hindu Calender. Add 3102 to the Year of Birth to get the Kali Year of Birth. From that value 4660 is deducted and the value is divided by 918. This gives the Beeja Kendra. Find out the Sin ( Bhuja ) of that, multiply it with 1187 seconds and add it to Jupiter’s longitude if the Kendra is in NCH and subtract it if it is in SCH.
The differential equation for that is
If Kali Year of birth is xyear
m = 1187 secs*( Sin ( xyear – 4660) * 360/918)
If m is in SCH, M = M – m
If m is in NCH, M = M +m , where M is the Mean Longitude of Jupiter
There are other minor perturbations which can be ignored.
( Lj = Mean Longitude of Jupiter; Ls – Mean Longitude of Saturn. These longitudes are Tropical or Sayana. ).