A planet can move backwards through the sky i.e. in an opposite direction to its usual movement (Direct Motion). During its retrograde phase a planet appears to move backwards through the zodiac. Apart from the Sun and the Moon all planets go through phases in which they change from a direct to retrograde motion as viewed from the Earth (Geocentric World-view). As stated, this is an effect created by the observer's location on the moving Earth. In reality (heliocentric view or outside view of the solar system) the planets continue to move in the same direction, anticlockwise around the Sun.
In the case of Mercury and Venus, the only two planets which orbit the Sun inside the Earth's own orbit, this occurs when they appear to be in fronnt of the Sun from a geocentric perspective (Their motion is direct when they are behind the Sun). Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, whose orbits all lie outside the Earth's own orbit, appear to turn retrograde during periods in which the Earth is moving more quickly than they are. This occurs when they form an opposition to the Sun - again, from a geocentric prespective.
In ephemerides planets in retrograde motion have an "R" printed next to them.
Before a planet changes its direction it from either retrograde to direct or vice versa its motion becomes increasingly slower until it appears to come to a stop. This is called the stationary phase.
The planets have different periods of retrograde motion:
- Mercury 3 times a year for 3 weeks,
- Venus roughly every 18 months for 40 to 44 days,
- Mars roughly every 26 months for 60 to 80 days,
- Jupiter roughly every 13 months for about 4 months,
- Saturn roughly every 12 1/2 months for about 4 1/2 months,
- Uranus roughly every 12 months for 20 about 5 months,
- Neptune roughly every 12 months for 5 months and 6 days,
- Pluto roughly every 12 months for 5 to 6 months.
Uranus, Neptune and Pluto are retrograde for about half the year.
Retrograde planets indicate energies of a more introverted quality. Which can means that it is usually difficult to find ways of expressing them directly. Before this can happen it is necessary for an individual to go through a long period of introspection in order to consciously come to terms with them. As with any difficult horoscope theme an individual can draw from an almost infinite variety of possibilites to express the energy of the planet in question. Secondary progressions are particularly interesting in this respect. It is a predictive method in which each tag after the date of birth equates to one year on an indivudal's life and is often used to highlight an individual's inner development. The retrograde Mercury or Venus in a natal chart will usually turn direct at some time during the course of a person's life making it easier to express their energies in a direct manner.
A retrograde planet in the natal chart has already passed over its natal position before the birth took place. For this reason retrograde planets can indicate something that a person may feel familiar with without having a rational explanation for this.
When transiting planets turn retrograde they pass over certain degrees of the zodiac a second time - or in some cases up to four times. Such transits indicate a deepening of the theme in question.