On Stage Lighting presents a simple Beam Angle Calculator to help you find the correct spotlight for your show.
If you need to project a gobo image to a certain size or the pool of a spotlight to be a specific width , you need to find out the beam angle . The calculation to find Beam Angle using the Throw Distance/Beam Diameter is simple trigonometry that we have compiled into the Beam Angle Calculator using Javascript.
Update:// There are now quite a few stage lighting calculators for your iPhone. Look at out Stage Lighting iPhone Apps page
Rob Sayer HND PGDip FHEA is a Senior Lecturer in Technical Theatre Production, mentor, and consultant in stage lighting and education. As a professional lighting designer, Rob designed and programmed theatre performances, music festivals and large corporate events for blue chip companies while travelling all over Europe. With a background in theatre, he combines traditional stage lighting knowledge alongside fast moving lighting and video technology in the world of commercial events.
please give an example how to calculate the beam angle