A synodic cycle measures successive returns of a planet to
its conjunction with the Sun, as seen from Earth. From the Greek sýnodos'meeting'.
The diagram above shows the synodic cycle of Venus, as seen
from Earth. The trail that has been picked out shows the geometrical
relationship that Venus makes with the Earth, beginning with the
superior conjunction of 11th January 2010 (at 22 Capricorn) and ending
with the completion of the cycle on 16th August 2011, (the next superior
conjunction at 23 Leo). As one cycle leads to another, Venus will trace
out an almost perfect pentagram over five cycles, which will take eight
years to complete.