The "Great Conjunction" of Jupiter and Saturn on December 21st means that these two planets will appear in the sky very close together...so close that you will be able to see both in a view through a small telescope.  The last time these planets appeared this close was in 1623, but the sun was in the way.  So the last time these planets were actually seen this close was in 1226.  Yes, this is a rare event, and hence the prefix "Great" in front of the word conjunction. It has been called "The Christmas Star" by news reports, and is certainly not the star of Bethlehem (remember that Harod couldn't see the star...everyone can watch Jupiter and Saturn).  Don't panic if it is cloudy on the 21st.  Go out a couple of days before the 21st and watch each clear night.  Use binoculars or a small telescope for a great view.

While calibrating telescopes at the Roll-Top Observatory at Turner Farm Observatory Park, Jeff Kretsch took the following photo at right: