Gathering of Planets On March 22nd, if you find some clear skies after sundown, you're in for a show that doesn't happen very often. Mercury, Venus, Mars, Saturn and Jupiter will all be in the sky, and they will all be viewable by eye. This won't happen again until 2008, so if you miss it, you've got four years to wait. Check out the NASA site for the best viewing times, and where to look.