Mercury first crosses the eventual direct-station degree while moving forward. It later reverses, returns to direct motion, and finally crosses its earlier retrograde-station degree. The two outside dates are conventionally called pre- and post-shadow; the retrograde interval is only between the stations.
Download 2027 dates as CSV ↓- 01 · DEGREE RETURNPre-shadow begins
- 02 · MOTION REVERSALStations retrograde
- 03 · MOTION RESUMESStations direct
- 04 · DEGREE RETURNPost-shadow ends
- 01 · DEGREE RETURNPre-shadow begins
- 02 · MOTION REVERSALStations retrograde
- 03 · MOTION RESUMESStations direct
- 04 · DEGREE RETURNPost-shadow ends
- 01 · DEGREE RETURNPre-shadow begins
- 02 · MOTION REVERSALStations retrograde
- 03 · MOTION RESUMESStations direct
- 04 · DEGREE RETURNPost-shadow ends
Reading this calendar
The listed dates describe motion in the sky, not events in a life. A nearby personal transit needs a birth chart and its own orb. The shadow label does not imply Mercury is retrograde throughout the full four-date span. Compare the 2027 station calendar or read the method before using another time zone.
Sources and boundaries
Station instants come from the site's independently calculated sky calendar; shadow dates are new longitude searches using the same Astronomy Engine 2.1.19 positions. NASA explains apparent retrograde motion. “Shadow” is an astrologers' degree-based label, not a separate physical event. All results use apparent geocentric tropical ecliptic longitude and UTC. Station inputs are rounded to the minute, and degree crossings to the second; another ephemeris may differ slightly.