In 1990, Mercury has four retrograde periods: in Capricorn, Taurus, Virgo and Sagittarius. The year opens with a retrograde carried over from the year before; it ends on January 19. The last begins on December 14 and runs into the new year.
Retrograde periods in 1990
December 30, 1989 – January 19, 1990
Over
- Shadow begins
- Retrograde begins
- Turns direct
- Shadow ends
- Sign
- Capricorn
- Length
- 20 days
April 23 – May 16
Over
- Shadow begins
- Retrograde begins
- Turns direct
- Shadow ends
- Sign
- Taurus
- Length
- 23 days
August 25 – September 17
Over
- Shadow begins
- Retrograde begins
- Turns direct
- Shadow ends
- Sign
- Virgo
- Length
- 23 days
December 14, 1990 – January 3, 1991
Over
- Shadow begins
- Retrograde begins
- Turns direct
- Shadow ends
- Sign
- from Capricorn into Sagittarius
- Length
- 20 days