**The Astronomical Foundations of
Astrology **

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**The
Ascendant is defined as the intersecting point between the Ecliptic and the
Celestial Horizon and is the Eastern Celestial Horizon. It is represented by
the formula**

**Tan
L = Sin E / cos E cos w - Sin w Tan A**

**where
A is Latitude of the place, w is the maximum declination of the Sun, E is the
Right Ascension of East Point ( Sayana
Kala Lagna ) & L - the Lagna.**

**Raseenam
Udayo Lagnam - Udaya
Lagna, the Ascendant, the
pivot of the horoscope, is the Eastern Celestial Horizon. In Astrology
everything is based on Lagna, Sarvam
Lagnepi Chinthayel.**

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**180
degrees opposite to the Ascendant is the Descendant, the Astha
Lagna and is the Western
Celestial Horizon.**

**Bhujamsa**** is
the degrees traversed by the planet in the Zodiac. In the mighty 360 degree
Circle, the planet may be anywhere and its position is its mean longitude. The
planet actually is in the ellipse and its position is the true longitude of
the planet.**

**If
the planet is say at 42 degrees, then the Equation of Bhuja states that its Bhujamsa is
42 degrees. That is in the first Oja
Pada, in the first quarter of 0-90 degrees, the Bhujamsa is the same.**

**If
the planet is say at 110 degrees, then the Equation of Bhuja states that its Bhujamsa is
70 degrees. That is in the first Yugma
Pada, in the second quarter of 90-180 degrees, the Bhujamsa is 180 -
bhuja.**

**If
the planet is say at 200 degrees, then the Equation of Bhuja states that its Bhujamsa is
20 degrees. That is in the second Oja
Pada, in the third quarter of 180-270 degrees, the Bhujamsa is bhuja -
180.**

**If
the planet is say at 300 degrees, then the Equation of Bhuja states that its Bhujamsa is
60 degrees. That is in the second Yugma
Pada, in the fourth quarter of 270-360 degrees, the Bhujamsa is 360 -
bhuja.**

**Bhuja
Jya**** is
Sin ( M ) and is the sine value of the Kendra. Bhuja
Jya is used in the
calculation of Epicycles, in calculating the Equation of Center for Moon,
Jupiter and Saturn.**

**The
Manda Phala, the Equation of Center is given by the formula**

**Equation
of Center, Mandaphala =Circumference of the Epicycle ( Parama Phala ) * Manda
Kendra Jya ( Sin M ).**

**This
is the equation used in calculating the 14 perturbations of the Moon, the five
of Jupiter and the six of Saturn.**