O

Occidental & Oriental

From cusp of tenth house westward to fourth via the descendant is occidental. The opposite half is oriental. To be "oriental in the figure" means being near the Ascendant, best suited to the Sun; to be "occidental in the figure" means being near the Descendant, best suited to the Moon. Planets are sometimes described as being occidental or oriental of the Sun. Occidental means setting after the Sun so visible in the evening; oriental means rising before the Sun, so visible in the morning. Ptolemy says: "When oriental, the influence is masculine; when occidental, feminine." This is a subtle influence, but he also says oriental planets are more powerful, especially when increasing in speed ("adding to proper motion"). Oriental planets are said to have "more height and hair", meaning that they have such an effect on the appearance of the native.

Occult

Hidden, or concealed.

Occult Knowledge

Secret knowledge, known only to the initiated.

Occultation

Planets occasionally obscure other planets or stars temporarily. The Moon, transiting a variable orbit, does so frequently. The phenomenon is termed occultation to distinguish it from eclipses. An occultation is equal to a powerful total or partile conjunction. [To be actually partile, these bodies should at the time have the same latitude and longitude.]

Old Aspects

Major Aspects.

Ophiuchus

The Serpent-Bearer, the so-called "13th Sign" of the Zodiac. Ophiuchus was one of the 48 constellations listed by Ptolemy, but was never considered a Sign of the Zodiac. The zodiacal Signs are particular divisions of the circle of the ecliptic into 12 equal parts of 30° each, based on the seasonal changes marked by the Equinoxes and the Solstices. Despite their names, the positions of the stellar constellations nowadays have no direct connection with the Signs, at least not in Western Tropical Astrology (compare Sidereal Zodiac).

Opposition

A generally adverse aspect of 180 degrees, depending on the planets involved.

Orb

An aspect between planets or sensitive points is usually allowed some inexactitude, which is called its orb of influence. This comes from the idea of a halo or aura surrounding a planet, comprising its rays. Traditional astrology allows different orbs for each of the planets, but modern astrology works primarily on an orb of aspect. Major aspects are allowed a greater orb than minor ones. For example, a conjunction is usually allowed an orb of 8 degrees, whereas a semi-sextile would only be allowed an orb of 2 degrees of arc. The Moon is usually allowed more orb than other planets, while faster planets are allowed more orb than slower ones. Greater orb is allowed in natal astrology than in mundane, where timing is more critical.

Orbit

Path described by an astronomical body (such as a moon or a planet) in its motion though space around another astronomical body (such as a planet or a star).

Oriental

See Occidental & Oriental.

Out-of-Sign

Aspect which, though within orb, is not within the bounds of the aspecting sign. For example, an out-of-sign conjunction of Mars and Venus, when Mars is in 28° Libra and Venus is in 2° Scorpio is much weaker than if Mars were at 7° Scorpio, even though the orb of aspect would still be 5°. Similarly, an out-of-sign square between Sun at 3° Aries and Saturn at 29° Gemini, is much less significant than an in-sign square with Saturn at 7° Cancer.

Outer Planets

Uranus, Neptune and Pluto. These planets, the furthest out in our Solar System, are invisible to the naked eye and so were only discovered in modern times, thanks to the invention of the telescope. They usually affect us at a very deep, subliminal level and the unconscious, generational effects are only brought to the surface when aspected by the Luminaries or other visible planets. Modern astrologers have incorporated them into astrological practice, but they are not generally considered by traditional astrologers, as they do not fit the classical symbolic structure of astrology.
[NOTE: Distant bodies in our solar system such as Chiron are not usually classed as Outer Planets, or even true planets (Chiron now seems more like a comet). Pluto has even recently been demoted by the IAU to the status of a "dwarf planet", but this does not diminish his astrological value. Other bodies such as Eris, a recently-discovered "dwarf planet" in the Kuiper Belt, are known to exist by science, but as yet have no accepted astrological significance.]