A conjunction is a close passage of one celestial body to another, or several in some cases, and an occultation is where the objects get close enough where one traverses in front of another, usually, but not always by the Moon. The can involve planets or stars. The Moon can occult a few of the brighter stars near the ecliptic, such as Regulus, Spica, Antares and Aldebaran, Also the Moon can pass in front of a few star clusters as well, such as the Pleiades.