"The maximum circle that passes through the east and west points of the horizon, through the zenith and the nadir, is called the First Vertical. In the drawing we see it represented in green.

Starting from the Zenith, in an east and west direction, the First Vertical is divided into twelve arcs of 30 ° each.

The poles of this domification are the North and South points of the horizon.

The position circles passing through the twelve points (in green) of the First Vertical resulting from the first subdivision are drawn from the poles.

The intersection of these circles of position with the Ecliptic identifies the cusps of the twelve houses (points in red).

Each house is therefore represented by the area of the Celestial Sphere between two adjacent position circles."

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I have a rather basic question on the Campanus Bhava system.

As I understand it, the Bhava cusps are calculated from the intersection of the prime vertical-north point joining lines with the ecliptic(after division of the prime vertical into 30 degree bits).

My question is this:

Do we take the 1st Bhava cusp as the start of the 1st Bhava, keep adding 30 degrees to it till we finish the 360 degrees of the zodiac and then place the remaining Bhava cups into their respective positions?

Or, Do we take the 1st Bhava cusp as the midpoint of the 1st Bhava and repeat the remaining steps?

It seems to me that the 1st Bhava cusp should be the start of the 1st Bhava since it represents the individual herself and thus the individual begins where their 1st bhava cusp begins. But I have also seen the bhava cusp being used as the midpoint of the 1st Bhava.

What is the appropriate calculation for the Campanus System? Any inputs on this would be much appreciated.

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