ONE QUESTION · A WORKED CHART
What does retrograde mean in my birth chart?
What does the R beside Mercury in my birth chart mean? It marks retrograde motion: Mercury appeared to move backwards through the zodiac from Earth's viewpoint at birth. Mercury does not reverse its orbit around the Sun; the apparent reversal comes from the relative motion of Earth and Mercury, as NASA's explanation of retrograde motion describes.
Position and direction are separate details. Phaladipika 4.1–2 counts motion among the sources of planetary strength, called cheshta bala, or strength through motion. Retrograde planets can gain this kind of strength. To interpret it, consider the planet's sign, house and associations as well.
See it in a chart
Example birth: 15 January 1990, 08:30 IST · New Delhi
The fictional Mercury is at 257.901002°, or Sagittarius 17.901002°, in the twelfth house with Saturn. Its longitude speed is −0.779110° per day; the negative value explains the R marker. Sagittarius is ruled by Jupiter, which is also retrograde and sits in Gemini in house six. Gemini is ruled by Mercury, so each occupies the other's sign: a sign exchange. That connects the two planets and their houses. Mars, by comparison, has a positive speed of 0.711704° per day and is direct. The sign of the speed tells you the direction; the longitude tells you the position.
- Mercury longitude
- 257.901002°
- Mercury sign
- Sagittarius
- Longitude speed
- -0.779110° per day
- Direction at birth
- Retrograde
For your own chart
Look at the planet's sign, house and companions before drawing meaning from the R. This chart also has retrograde Venus and Jupiter, while Mars is direct. A birth-chart marker describes motion at birth; to ask whether Mercury is retrograde on another date, consult that date's transit positions.
For reflection, read the R alongside the placement. It is not a personality flaw or a measure of how easily you communicate.
For astrologers: calculation details
Fictional Demo Chart A · 15 January 1990, 08:30 IST (UTC+05:30)
New Delhi, India; 28.6139° N, 77.2090° E
Lahiri sidereal zodiac; mean nodes; whole-sign houses; geocentric geometric positions; Vimshottari with a 365.25636-day year. UTC birth instant: 1990-01-15T03:00:00Z. Reference instant: 2026-09-28T06:30:00Z.
Angles are rounded to six decimal places; arithmetic uses the saved full values. Period boundaries are displayed to the nearest second in IST. These settings describe the calculation, not the precision of a birth record.
Follow the calculation
- The demo Mercury is at 257.901002°, or Sagittarius 17.901002°. Position and direction are separate columns.
- Its instantaneous longitude speed is -0.779110° per day. The negative sign is the reason the chart marks it retrograde.
- For contrast, the demo Mars has a positive speed of 0.711704° per day and is direct. Neither speed changes which sign contains the planet at the birth instant.