"In astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, planets, the astrological aspects, and sensitive angles at the time of an event, such as the moment of a person's birth. The word horoscope is derived from Greek words meaning "a look at the hours" (horoskopos, pl. horoskopoi, or "marker(s) of the hour.") Other commonly used names for the horoscope in English include astrological chart, astro-chart, celestial map, sky-map, star-chart, cosmogram, vitasphere, radical chart, radix, chart wheel, or simply chart."
"It is used as a method of divination regarding events relating to the point in time it represents and forms the basis of the horoscopic traditions of astrology. However, no studies have shown any scientific support for the accuracy of horoscopes, and the methods used to make interpretations are, at best, pseudo-scientific."
"In common usage, horoscope often refers to an astrologer's interpretation, usually through a system of Sun sign astrology or based on calendar significance of an event, as in Chinese astrology. In particular, many newspapers and magazines carry predictive columns based on celestial influences in relation to the zodiacal placement of the Sun on the day of a person's birth, identifying the individual's Sun sign or "star sign" based on a conventional zodiac (which is not the celestial one). Such a concept is distinct from horoscopes as typically employed, where only the traditional zodiacal placement of the Sun is considered in interpretation. While this modern usage is perhaps the most popular in the colloquial lexicon, this article will focus primarily on the traditional concept."
Construction of a horoscope in Western Astrology
To create a horoscope, an astrologer first has to ascertain the exact time and place of the subject's birth, or the initiation of an event. The local standard time (adjusting for any daylight saving time or war time) is then converted into Greenwich Mean Time or Universal Time at that same instant. The astrologer then has to convert this into the local sidereal time at birth in order to be able to calculate the ascendant and midheaven. The astrologer will next consult a set of tables called an ephemeris, which lists the location of the Sun, Moon and planets for a particular year, date and sidereal time, with respect to the northern hemisphere vernal equinox or the fixed stars (depending on which astrological system is being used). The astrologer then adds or subtracts the difference between the longitude of Greenwich and the longitude of the place in question to determine the true local mean time (LMT) at the place of birth to show where planets would be visible above the horizon at the precise time and place in question. Planets hidden from view beneath the earth are also shown in the horoscope.
The horoscope 12 sectors around the circle of the ecliptic, starting from the eastern horizon with the ascendant or rising sign. These 12 sectors are called the houses and numerous systems for calculating these divisions exist. Tables of houses have been published since the 19th Century to make this otherwise demanding task easier."
"The astrological symbols/glyphs used in Western astrology to represent the planets in astrologyThe chart thus begins with a framework of 12 houses. Upon this the signs of the zodiac are superimposed. In the equal house system the cusp between any two houses will fall at the same degree for each of the at 12° of Leo, the second house will begin at 12° of Virgo, the third at 12° Libra, and so on. In house systems that take into consideration the effects of the angle of intersection between the planes of the horizon and the ecliptic, the calculations are more complicated. For these calculations it is essential to know the latitude of the event. Tables are available for these calculations, but they are now commonly calculated by computer. Most astrology computer programs allow the user to choose from a variety of house systems."
Placements of the planets
"Having established the relative positions of the signs in the houses, the astrologer positions the sun, moon, and planets at their proper celestial longitudes. Some astrologers also take note of minor planetary bodies, fixed stars, asteroids (for example, Chiron) and other mathematically calculated points and angles such as the vertex, equatorial ascendant, etc. Many astrologers also use what are commonly referred to as Arabic parts (or Greek Lots), the most common of which is the Part of Fortune (Pars Fortunae)....