many as 10 independently controlled prisms and lenses to focus and shape the beam. Pattern wheels with gobos and gate shutters to change the shape of the beam or project images. Some fixtures have motors to rotate the gobo in its housing to create spinning effects, or use their complicated lens systems to achieve the same effect. Automated framing shutters to further shape the beam and control unwanted spill. These fixtures also use motors to enable physical movement of the light beam by either: Pivoting an automated mirror which reflects the beam along X & Y axes, or Attaching the entire fixture lens train to a yoke with motorized pan & tilt Note that fixtures which use the former method are not technically “moving heads”, since the light source itself does not move. However, the term “moving head” is used interchangeably throughout this article. On a moving head the glass gobos could have some fault caused by back-reflections of the light on the lens, to solve this defect can be used antireflections gobo. Usage Intelligent lights (now commonly referred to as automated or moving heads), can be used wherever there is a need for powerful lighting which must be capable of rapid and extreme changes of mood and effects. Moving heads would, therefore, be inappropriate in a setting which does not require strong lighting (such as a home) or where the “quality” of the light required does not vary excessively (although it may need to be very strong for a venue like a stadium). Naturally, there are exceptions to this rule, most notably the use of large numbers of moving heads for international sporting events, such as the Commonwealth Games or Olympic Games, where many thousands of separate automated fixtures are often used to light the opening and closing ceremonies. The 2008 Summer Olympics, in Beijing, had a rig of around 2,300 intelligent fixtures which is "the largest single automated lighting system ever assembled for a single event" Usually, however, the use of intelligent lights is confined to theatre, concerts, nightclubs, and churches where the versatility of these fixtures can be utilised to its best extent. In these applications, the uses of fixtures can be informally grouped into two categories: active and passive (although these are not standardised terms). Passive use of automated lighting involves utilizing their versatility to perform tasks which would otherwise require many conventional lights to accomplish.