Midheaven is the part of the sky at the time of birth, where the ecliptic, crosses the Meridian. It is the Mid of heaven in our chart, the highest point which we call Zenith. In the House Division System, Placidus which mainly is used by midheaven is considered the cusp of the 10th House.
The cusp of the 10th House is of great importance in a chart with the ascendant, as it describes the point of where we can reach our social status in our lives. When we have significant aspects from midheaven, it marks changes according to what they represent where the planets fall.
Midheaven are the aims (physically and mentally) of career, vocation, reputation which we can or cannot pursue. It is the cusp of the 10th which refers to our social recognition while parallel shows our social destination, our social status. Midheaven refers to a parent which is the person’s social model, who may be the father, mother, depending on the role he/she plays in the life of the individual.
In the House System Placidus, which mainly is used in midheaven is the cusp of the 10th House.
– House Division and House Division Systems
The House Division consists of tables showing the degrees of zodiacs which occupy the cusps of Houses in different latitudes for every degree of Right Ascension or for every 4 minutes of sidereal time. Raphael tables contain such House Divisions. There is much argument regarding the various systems of calculating the cusps of the Houses, while a point could be used to locate the degree on the horizon every two hours. The general opinion is that none of the existing methods are correct for all latitudes, even if they are near enough, for practical purposes. The four most popular systems are:
Campanus.The vertical circle from the zenith to the cast and west points of the Horizon is trisected. Through these points are drawn great circles, the House circles, from the north and south points of the Horizon. Consequently the intersections will be at an altitude of 30 and 60 degrees above the horizon, on both cast and west branches of the first vertical. This divides the sky into six great sectors. Similarly divide the hemisphere below the horizon. The House Cusps are the points at which the ecliptic at that moment intersects the horizon.
Regiomontanus. (The System of Place) The celestial circle is trisected, instead of the prime vertical, and great circles extend from north and south points of the horizon to the points of trisection. The house cusps are at the points at which the ecliptic intersects the horizon. At the Equator the two systems give the same cusps, the disparity increasing as one approaches the Earth’s poles.
Koch. This system is named after the astrologer Walter Koch. In German-speaking countries it is known as the System of Houses on places of birth. The system is based on more than the other on place of birth. The cusps of the Houses in this system are calculated with the same polar height, i.e. with the polar height of the place of birth, which has the same value as the latitude of the place.
Horizontal. Starting with great circles at the meridian and ante-meridian, the horizon and the prime vertical, add other great circles from Zenith to Nadir which trisect each quadrant of the horizon. The cusps will then be the points at which on a given moment the ecliptic intersects the vertical circles.
Placidus (Time System) Instead of using great circles, the diurnal motion of the Earth causes a celestial object to intersect the cusp of the 12th House, after a sidereal-time interval equal to one-third of its semi-diurnal arc; to intersect the cusp of the 11th House after a sidereal-time interval equal to two-thirds of its semi-diurnal arc; and to culminate at the meridian after an interval of sidereal time that corresponds to the semi-diurnal arc. The semi-arc from the meridian that intersects the Eastern horizon gives the Ascendant; and the 2nd and 3rd house cusps are similarly extended below the horizon. The Placidian Cusps are the main of the House Division System.
Equal Houses. The system of equal Houses they call isometric as well. It divides the Zodiac into twelve Houses of 30 ° degrees, starting with the Ascendant. A series of House tables for width of 40 degrees North Latitude, which is approximately the latitude of New York, which can be seen in a comparison of these four systems, and can be found in American Newspapers for Astrology in the year 1941. The 10th House is common in all four systems and it is theoretically correct. The differences appear in the intermediate cusps, between the descendant and midheaven. The horoscope is also the same for three of the four systems, but the horizontal system has its own horoscope. Different Latitudes require different sets of house divisions. Many volumes have been published containing the House Divisions for all latitudes, most however, are limited to the Placidus system, which is generally the one used most.