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Awash With Color – How We Light a 60 ft. Planetarium Dome

            As the planetarium projectionist I get the pleasure of sitting behind the scenes and watching the variety of reactions people can have to what they experience under our dome.  Being the person at the controls I can rotate the sky, fly you out to the furthest reaches of our universe, dazzle you with laser light, or make you tap your feet with our music and sound system.  There is certainly a myriad of ways I can impress people while in the planetarium.  It’s a very unique experience unlike what you would get in any other theater. 

            One of the things I see and hear from people after a show is that when they leave the theater they look around trying to figure out where everything is coming from.  All they see is a dome above, the circular wall of the theater, and a place to sit. Where is all the sound coming from and where are the speakers? Where do the lasers come from? How do they get the image on the dome? And, how do they make the dome change colors like that?

            Yes, one of the things people enjoy when they wait for their feature presentation to start is what I refer to as the “walk-in show.”  This little bit of eye candy is typically a small cove light presentation coupled with some nice music, and laser light effects. 

     The dome is lit by what are called cove lights.   These cove lights are small, wand-shaped LED lighting modules about a foot in length that run end after end all along the inside wall of the planetarium theater area.  As you sit in the planetarium theater you’re aware that you’re in a circular room with a dome above you.  Well, behind that circular wall is the actual work-area of the planetarium and it’s where we hide most of our devices: projectors, lasers, wires, cables, microphones, mixing boards, computer monitors, etc.   

            It’s also where we hide the cove lights.  These cove lights look kind of like braces on someone’s teeth as they’re attached to the inside upper lip of the theater wall which is just below the lower lip of the dome up above.  This obscure location allows us to angle the lights in such a way that we can light up the entire 60 foot dome with color uniformly from bottom to top.

            But how do we make all those different light patterns?

Every single foot-long piece of cove lighting has an individual number assigned to it and every unit has a wire running from it to a central computer located underneath the planetarium.  That’s right, as you sit in the theater there is a whole other room under your feet filled with computers that make the planetarium experience possible.

            Well, we have a lot of computers that run all the various pieces of equipment we have, and one of those computers is dedicated just to the cove lighting system.  From that computer I can create patterns where I can lump cove light units together, control them individually, rotate them in clusters, change their colors all at once, or anything else I can think of. 

full dome

            I can make half the dome red and the other half blue.  I can make the entire dome dark but for one purple light spinning around the room.  I can simulate a sunset or I can demonstrate the Visual Spectrum from violet to red.

Once I have the patterns figured out the way I want them I can create cove light shows.  These shows are made when I program these patterns to operate in a certain way, for a certain amount of time, and in conjunction with other devices at my disposal like lasers, back lights on the speakers, pit lighting and other lighting options.  It’s all a choreography of light.

            In short, it comes down to that there are LED lighting units located behind the wall of where you’re sitting that shine up on the dome above you that’s just a tad wider than the rest of the room.  Each LED light has its own name and every foot-long unit that surrounds the 360 degree room is patched into one computer that will let me manipulate them in whatever way I want. 

            With a little bit of programming I can create a brief show that uses impressive laser lights and LED cove lights for people to enjoy while they sit in the theater and wait for their show to start. 

            So next time you visit the planetarium try and make a little time to come early so you can enjoy the vibrant enclosure of the cove lit dome.

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