House longitudes calculation

Proastro provides you 6 ways to calculate the longitude of houses.

  1. Hindus' system or Porphyre’s system:
  2. The meridian circle gives you center of houses X and IV, as it intersects with the ecliptic circle. Intersections between horizon and ecliptic give you the center of houses I and VII. Centers of other houses are founded dividing by 3 each of the forth above sectors.
    This is the system you should use to do Hindu Astrology.

  3. Alcabitius' system:
  4. The semi-diurnal arc of ascendant is divided in three equal parts making 2 points, 11 and 12. Polar circles that pass through those points intersect the ecliptic and give the XI and XII houses longitudes. We do the same with the descendant to get houses IX and VIII. Other houses are at the opposite of those already found.


    Alcabitius

  5. Abenragel's system:
  6. The same as the above, except that points 11 and 12 are crossed by position circles instead of hour circles.


    Abenragel

  7. Campanus' system:
  8. Meridian and horizontal circles are two perpendicular plans giving four dihedral angles. Each of those four angles is divided in three equal dihedral angles of 30°. This gives us 6 circle that intersects the ecliptic circle in 12 points, being the 12 houses.


    Campanus

  9. Regiomontanus' system:
  10. With this system, the position circles must divide the equator in equal part, for any geographic latitude.


    Regiomontanus

  11. Placidus' system:

This system divides each semi diurnal and each semi nocturnal arc in equal parts. This system cannot give house longitudes for latitude near North or South Pole. Proastro only give an approximation of the houses longitude for this system. This approximation is not restricted to high latitudes (near the pole).

See also:

Bibliography