Western Astrology has been practised for thousands of years in Arabia and Europe. Western astrology is geocentric, that is, it considers the Earth as the centre around which the Sun revolves. Modern astrology has as its roots the ancient celestial omen reading of Mesopotamia. The Mesopotamians lived in the area of modern-day Iraq betwen the Rivers of the Tigris and the Euphrates. They included the Sumerians, the Akkadians, the Babylonians and the Assyrians.
The Babylonians (Chaldean Astrology) began to interpret the celestial cycles rather than random events which developed into astrology proper. But it wasn't until the Ancient Greeks that the ecliptic (Sun's path) was measured against the Earth and an exact solar calendar could be drawn up. Planets could now be fixed relative to the solstice and equinox points rather than simply relative to the four compass directions and the zenith and nadir points relative to the observer.
In order to construct a horoscope, you need to have an ephemeris to look up the planet tables, an atlas to determine the longitude and latitude of the place in question, a Table of Houses for detemining the Ascendant and the division of the houses. Special astrological software that is now widely available has made light work of the often complex mathematical calculations involved with complex charts involving harmonics and progressions.
Neptune - Dreams, illusions, deceptions, the arts.
Pluto - Elimination, death, birth, regeneration.
North Node - Dragon's head, new and unfamiliar circumstances and activies.
South Node - Dragon's tail, habit patterns from childhood or from past lives.
The horoscope is divided into 12 houses. In Western Astrology there are many different methods of making these divisions. By the way, there is no astronomically perfect way of calculating the houses. Every system has its weakness.
The Twelve Houses
The querent. Personal life and appearance, beginnings, accidents, new projects, length of life. East. Angular.
Finances, values, lost or stolen objects, possessions, potential poverty or wealth, resources, material things desired, business transactions, earnings (work). East North-East. Succedent.
Siblings, relatives, neighbours. Short journeys. Schooling, early education. Cars. Personal communication, letters, emails, advice. Gossip, rumours, news. North North-East. Cadent.
Home, parents, father, domestic issues, buried treasure, land, real estate, inheritances from parents, houses, farms, agriculture, old age, mines. The end of any matter. North. Angular.
Children, women, luxury, affairs, gambling, hobbies, stocks, romance, pregnancy, elections, entertainment, feasts, eating, drinking, parties, fun. Personal creativity. Bodies of water, rain. Teaching. North North-west. Succedent.
Health, illness, diseases, injuries, misfortunes. Hygiene, healing. Daily work, daily routines. Pets, small animals. Servants, employees. West North-west. Cadent.
Partner (marriage and business), lover. Divorce, lawsuits, contracts. Quarrels, open rivals, competitors. Thieves, robbers, dishonours. Any unidentified person. The astrologer. West. Angular.
Shared resources, death, birth. Surgery. Transformations, occult. Taxes, debts, mortgages and loans. Legacies, inheritance from other than parents, other people's money or resources, corporate money. Investigations. Poverty, suffering, dangers. Sleep. West South-West. Succedent.
Long-distance travel, religion, philosophy, education, learning, religion. Lawyers, professionals. Dreams, divination. Wisdom. The arts. Public communication, media, publishing. South South-West. Cadent.
Friends, sources of help. Protection, riches, presents. good fortune, Joy, hopes and wishes, praise, confidence, goals. Social activities, group endeavours. South South-East. Succedent.
Loss, imprisonment, secret enemies. REtreat and solitude. Widowhood, fears. Secrets, suffering, afflictions. Large animals. Hidden life, unconscious thoughts. Institutions, hospitalisation. Suicide, murder. Vagabonds, prostitues, beggars. Charity. Drugs and alcohol. South South-West. Cadent.
The Different Systems of Houses
The Ecliptic Systems:
Where the ecliptic is divided to determine the house cusps.
The Equal House System
The oldest and most popular system, the Equal House system, dates back to 3000 BC. The Ascendant marks the cusp (beginning) of the First House and the Descendant the cusp of the Seventh House. The rest is divided into 12 equal houses, hence the name. The beauty of this system is its mathematical simplicity. The drawback is that the cusps of the Fourth and Tenth Houses usually do not coincide with the Midheaven and the IC as in other systems.
The Porphyry System
This system was developed in the 3rd century AD. The Midheaven is taken as the cusp of the Tenth House and the quadrants are divided equally. Not much in use today.
Other examples are the Natural Graduation House System and the M-House Method.
The Space Systems:
Where another great circle such as the celestial equator, the horizon or the prime vertical is divided to determine the house cusps and projected onto the ecliptic.
The Campanus House System
Johannes Campanus was a famous mathematician of the 13th century. He decided to divide the prime vertical into equal segments. This system does not work in localities of high latitudes.
The Regiomontanus House System
Johannes Muller (Regiomontanus) modified the Campanus system in the 15th century. He chose the celestial equator as his primary frame of reference. This sytem was very popular until 1800 and is still used in Europe, as well as for Horary and Electional Astrology.
Other examples are the Morinus House System and the East Point House System.
The Time Systems:
Where the time taken for the Ascendant or Midheaven to travel an arc of the celestial sphere is equally divided to determine the house cusps.
The Placidus House System
Placidus de Titus, a Spanish monk, developed this in the 17th century. It is very complicated to calculate. This sytem became very popular after the 19th century astrologer Raphael published an almanac
including a Placidean Table of Houses. This system does not work at all in high latitudes. This is, however, the most popular house system in use today.
The Koch House System (Birthplace House System)
Dr Walter Koch published this system in 1971 and it is based on complex trigonokmetry using the arc of oblique ascension at the place of birth. This system also fails in the highest latitudes.
The Topocentric House System
This system is a refinement of the Placidus House System. This system was not derived theoretically. It was developed in Argentina by Wendel Polich and A. P. Nelson page who studied the events in the life of a person who had a precise time of birth. This system works in all places.
If you are interested in learning more about Western astrology, I can recommend these books: