How Often Do the Planets Align?
The nine planets in this solar system somewhat align once every 500 years and are grouped within 30 degrees every one to three alignments. When astrologers describe the planets as being aligned, they do not necessarily mean that all of the planets line up on a perfectly straight line. The last alignment within 30 degrees occurred in 561 B.C., and the next alignment within 30 degrees takes place in 2854.
All of the planets are within the exact same quadrant – within about 90 degrees of each other – about once every 200 years, but they line up more loosely on a more frequent basis. There is never an exact alignment from the vantage point of the sun because of the differences between the axial tilts of the planets in this solar system.