Does a retrograde planet reverse its orbit?
No. Retrograde motion is an apparent westward drift against the stars, caused by how Earth and the planet move relative to each other.
STEP 1
What retrograde describes
Retrograde describes a period when a planet appears to move east to west against the background stars, opposite to its usual drift. The planet keeps moving forward in its orbit.
STEP 2
The Mars example
Earth and Mars both orbit the Sun. As Earth catches up with Mars and passes it, our changing line of sight makes Mars appear to slip backward against the distant stars, much as a slower car seems to drift back when you overtake it.
STEP 3
Read the numbers
For a simple example, suppose a planet’s ecliptic longitude is 120.5° on one date and 120.3° on the next. That decrease shows apparent retrograde motion. These are illustrative numbers. When comparing a real table, also check for the 360°–0° boundary: a change from 359.9° to 0.1° is forward motion across zero, not a large backward jump.
STEP 4
Keep description and interpretation apart
Astronomy describes where a planet appears in the sky. Astrological readings of retrograde periods are a separate interpretive layer. AstroAunty does not calculate retrograde periods.