Retrograde and direct motion

An Earth-based direction, not a reversed orbit

The Earth and other planets move while the viewing geometry changes. A planet's apparent progress around the zodiac can slow and reverse even though its orbital motion continues. The coordinate is measured from Earth's centre using the selected zodiac; it is not the direction the planet would appear to move across your local horizon during a night.

A positive speed is marked Direct and a negative speed Retrograde. The displayed number has units of degrees per day. It describes the local rate around the sample, not a fixed speed that can be extended indefinitely to predict later positions.

Do not infer motion from rounded degrees alone

Near a station, successive positions may look almost identical. Rounding can conceal the difference, especially in a source that prints only arcminutes. Read the signed speed and motion label rather than deciding that an unchanged printed degree means stationary. Sky Degrees prints arcseconds, but a small number is still different from zero.

The zodiac also wraps at 360°. A move from the end of Pisces to the beginning of Aries can have a smaller printed longitude while remaining direct. The runtime evaluates direction around the circle; plain subtraction across that boundary needs adjustment.

A daily sample is not an event search

A station is a change of direction, where the longitudinal rate passes through zero. Negative speed at one daily sample and positive speed at the next identify an interval containing a direction change, assuming continuous motion. They do not supply its exact hour or minute, and linear interpolation would be an additional approximation.

Sky Degrees does not perform an exact station search in this table. The Stationary label applies if the returned speed is exactly zero; there is no general near-station threshold that converts every small speed to zero. Check the actual sample instead of assigning one motion status to an entire civil date.

Keep observation and interpretation separate

Astrological traditions give retrograde motion symbolic meanings. The calculated direction does not establish that communication, travel or a personal decision will go wrong. First record the planet, instant, longitude and signed speed; treat any reflection on those data as a separate interpretive step.

Common questions