Mercury never appears very far from the Sun (between 17 and 28 degrees away, the variation being due to its highly eccentric orbit). Consequently it can only be seen with the naked eye when it is low down in twilight (shortly after sunset or before sunrise) and it is never seen in fully dark skies. Mercury typically makes three morning appearances and three evening appearances each year, though for any given location on Earth, Mercury will only be well placed for viewing on about half of these occasions because of the length of local twilight and the angle of the ecliptic to the local horizon.