After Friday's spectacle, a "planet parade" of this size won't appear in the night sky for several years, experts say.

While all seven planets could appear in some form in parts of the U.S., not all of them will be visible to the naked eye. Here's what to know.

When we have five or more planets filing into a small sky area, an alignment is upgraded to parade status. Parade is not an official astronomical term and is used fast, loose and with a touch more whimsy than space experts usually allow for.