Animation showing a typical evening apparition of Venus, with the planet plotted at 15-day intervals for a time 45 minutes after local sunset. This particular apparition took place between November 2003 and June 2004. Greatest elongation (46º East of the Sun) took place on March 29th 2004, when the planet showed a half phase through telescopes. The 2003-4 apparition ended with a 'transit of Venus' (when the planet crossed the face of the Sun) on June 7th-8th 2004.

Viewed from the Earth, Venus shows the greatest range in apparent size of all the planets; it typically ranges from just 10" (i.e. 10 arcseconds, at superior conjunction) to about 60" (60 arcseconds, or 1 minute of arc, at inferior conjunction). In the animation, Venus' apparent size varies from 11".4 (on November 30th 2003) to 55" (on May 28th 2004). The apparent magnitude of the planet varies from -3.8 (on November 30th 2003) to -4.1 (on May 28th 2004). Greatest brilliancy (-4.4) was reached in early May (for further details on Venus' morning/evening visibility cycles, see the Planet Movements article).

The animation applies to a latitude of 52º North (applicable to Northern Europe, Canada, Russia). The numbers shown in grey on the left (10º, 20º and 30º) indicate the angular elevation or altitude (i.e. the angle above the horizon) of any given celestial body for that particular latitude; hence on January 29th 2004, some 45 minutes after sunset, Venus was in the South-west at about 23º above the horizon.

The changing brightness of the sky reflects the changing length of twilight as the seasons progress from Winter to Spring to Summer in the Northern hemisphere. Note the extent of the horizon covered by Venus during the course of its apparition, as the planet follows the changing position of the setting Sun through the year; the illuminated section of the planet faces towards the Sun, which, at the dates and times shown, is several degrees below the horizon.

The orbital periods of Venus and the Earth are related such that 13 Venusian years (13 x 224.7 days = 2921 days) are approximately equal to 8 Earth years (8 x 365.25 days = 2922 days). Hence, when seen from the Earth, Venus appears in very nearly the same position in the sky at any given 8-year interval. The evening apparition shown here will therefore repeat, to within a couple of days, between November 2011 and June 2012 (there will be another transit of Venus on June 5th-6th 2012). Transits do not occur every 8 years, however, since the relationship between the two orbits is not an exact one. After 2012, there will be no Venus transits until the year 2117.

During the course of each 8-year period, Venus undergoes five morning apparitions and five evening apparitions.

Copyright © Martin J. Powell  Feb 2007/Oct 2008