Editing Horoscope (section)

==Concepts in Western astrology==
[[File:Astrological birth chart for Charles I, King of England Wellcome L0040329.jpg|thumb|Astrological birth chart for [[Charles I of England]]]]
{{Main|Western astrology}}

* The native is the subject of the event (a birth, for example) being charted at a particular time and place, and is considered to be at the centre of the celestial sphere.
* The celestial sphere is an imaginary sphere onto which the zodiac, constellations and planets are projected, loosely based on the view of the sky above from Earth.
* The plane of the equator is the plane of the Earth's [[equator]] projected into space.
* The plane of the ecliptic is defined by the orbits of the Earth and the [[Sun (astrology)|Sun]]. For practical purposes, the plane of the equator and the plane of the [[ecliptic]] maintain a constant inclination to each other of approximately 23.5°.
* The plane of the horizon is centred on the native, and is tangential to the Earth at that point. In a sphere whose radius is infinitely large, this plane may be treated as nearly equivalent to the parallel plane, with its centre at the Earth's centre. This greatly simplifies the geometry of the horoscope, but does not take into account that the native is in motion. Some writers on astrology have thus considered the effects of [[parallax]], but most would agree that (apart from that of the Moon) they are relatively minor.{{Citation needed|date=February 2008}} 

===Angles===
There are four primary angles in the horoscope which are thought to influence key areas and moments in a native's lifetime, or within a given day or time. These are, in order of power:

* First House ([[Ascendant]], East Angle, rising sign, or ASC/AC)
* Tenth House ([[Midheaven]], Medi Coeli (midheaven), North Angle, MC)
* Seventh House ([[Descendant (astrology)|Descendant]], West Angle, setting sign, DSC/DC)
* Fourth House ([[Imum Coeli]] – South Angle, lower-heaven, IC)

The [[ascendant]] is the easternmost (or sunrise point) where the ecliptic and horizon intersect; the ascendant and the [[midheaven]] are considered the most important angles in the horoscope by the vast majority of astrologers. In most systems of house division, the ASC is the cusp of the 1st house and the MC is the cusp of the 10th house. 

Generally, on an astrological chart, each of these four angles are roughly 90° from the next, forming a cross shape (two oppositions, 180° each, forming a 360° sphere). This cross formation is made up of the points of east-west, north-south, or 1st house-7th house, 10th house-4th house (give or take, based on speed of orbit and degree). A simplistic comparison would be a clock face, with the 1st house and 7th house being placed at 9 and 3 o'clock, and the 10th and 4th houses placed at 12 and 6 o'clock, respectively. The placement of the planetary ruler of the ascendant, called the [[Chart Ruler]], is also considered to be significant; The point in the west diametrically opposing the ascendant is called the descendant, normally the cusp of the 7th house; and the point opposing the MC is the cusp of the 4th house, the northernmost point of the chart, called the [[Imum Coeli]] or IC.

In creating a horoscope, the ascendant is traditionally placed at the "nine o'clock" position on the left-hand side of the chart wheel (though traditional rectangular chart formats need not follow this convention). During the course of a day, because of the Earth's rotation, the entire circle of the ecliptic will pass through the ascendant and will be advanced by about 1°. In an astrological chart, the ascendant progresses and changes zodiac signs roughly every two hours (give or take), advancing about one degree every five minutes. This movement provides us with the term "rising" sign, which is the sign of the zodiac "rising" over the eastern horizon at the moment of birth. This point is thought to affect how we are perceived by others, based on the zodiac sign on the ascendant at the time of birth. The point on the ecliptic that is 90° above the plane of the horizon at the time is called the Midheaven, or Medium Coeli (MC), placed at the "twelve o'clock position" effectively where the Sun would be if the birth time was midday. This area is thought to have greatest significance on one's career and public image.

===The Zodiac===
[[File:Astro signs.svg|thumb|right|The [[astrological symbols]]/[[glyphs]] used in Western astrology to represent the [[astrological signs]] ([[Zodiac]])]]

{{Main|Zodiac}}

The Zodiac, or "circle of animals" is a zone or belt in space projected onto the celestial sphere through which, from our viewpoint, the planets move. A symbolic geometric construction around 16 degrees wide, it is divided into 12 signs, each of 30 degrees longitude (making 360 degrees, a full circle), with the ecliptic, the apparent path of the Sun, as its middle line.<ref name="oxford-def">{{cite web |title=zodiac |url=https://en.oxforddictionaries.com/definition/zodiac |archive-url=https://web.archive.org/web/20160926223903/https://en.oxforddictionaries.com/definition/zodiac |url-status=dead |archive-date=September 26, 2016 |website=Oxford Dictionaries |access-date=19 September 2017}}</ref> The tropical zodiac used by most Western astrologers has its beginning at the exact moment that the Sun crosses the [[celestial equator]] and enters the zodiacal sign of [[Aries (astrology)|Aries]]. Some Western astrologers use the [[Sidereal astrology|sidereal zodiac]] favored by Indian ("Jyotish") astrologers, which is based more closely on actual positions of constellations in the heavens, as opposed to the tropical zodiac, which is a moveable format based on the seasons.

The tropical zodiac defines the vernal point (the first day of spring in the northern hemisphere) as the first degree of Aries, but the sidereal zodiac allows it to precess. Many people are confused regarding the difference between the sidereal zodiac and the tropical zodiac signs. Because of a "wobble" in the Earth's axis of rotation over a period of about 26,000 years (often called a "[[great year]]"), the rate at which the vernal equinox precesses in the heavens is approximately 0 deg, 0 min, 50.23 seconds a year, drifting by one degree every 72 years. [[Precession of the equinoxes]] thus occurs at a rate of roughly 5 arc minutes of a degree every 6 years. The tropical signs relate to the seasons and not the stars.<ref name="Rochberg">{{ cite journal | last=Rochberg | first=Francesca | author-link=Francesca Rochberg | date=1988 | title=Babylonian Horoscopes | series=Transactions of the American Philosophical Society | volume=88 | issue=1 | pages=i–164 | jstor=1006632 | doi=10.2307/1006632 | publisher=American Philosophical Society }}</ref> Here is an example: a person born on, say August 28, 2002, would come to understand that their Sun sign was in Virgo according to [[Western astrology]] (conventional Sun sign dates August 23, to September 22, of every year), but Sun on that same calendar date of the year 2002 was in the [[Leo (constellation)|constellation Leo]] (where it had been since August 10, 2002, and would remain until September 15, when it would then finally cross into Virgo).

The sidereal signs and the tropical signs are both geometrical conventions of 30° each, whereas the zodiacal constellations are pictorial representations of mythological figures projected onto the celestial sphere based on patterns of visible star groupings, none of which occupy precisely 30° of the ecliptic. So constellations and signs are not the same, although for historical reasons they might have the same names.<ref>{{cite web |last=Burk |first=Kevin |url=http://www.astrologycom.com/precession.html |title=Astrology on the Web: Stars and Signs |access-date=2011-10-11 |archive-date=2011-10-19 |archive-url=https://web.archive.org/web/20111019194236/http://www.astrologycom.com/precession.html |url-status=live }}</ref>

Some astrologers do not use the signs of the zodiac at all, focusing more instead on the [[astrological aspects]] and other features of the horoscope. The [[Sun (astrology)|sun sign]] is the sign of the zodiac in which the Sun is located for the native. This is the single astrological fact familiar to most people. If an event occurs at sunrise the ascendant and sun sign will be the same; other rising signs can then be estimated at two-hour intervals from there. A cusp is the boundary between two signs or houses. For some, the cusp includes a small portion of the two signs or houses under consideration.