Annual parallax Geocentric or diurnal parallax varies with the daily spinning of the Earth around its axis.
Annual parallax is caused by the Earth's yearly orbit around the Sun.
If the star is not in the plane of the ecliptic, there is a shift in ecliptic latitude too. So during the year, the star appears to trace out a parallactic ellipse, which is a reflection of the Earth's orbit. Previous section . Next section . Return to index .