Orion1 Base Light Curtain, Transmitter + Receiver, Resolution=30mm (hand), Protected height=900mm, Range=0.2-19m, Type 4. Orion1 Base is an easy to use light curtain with compact dimensions and two resolutions for detection of fingers and hands. Light curtains are usually used closed to the hazardous zone when repeated access to the machine is necessary, for example manually serviced machines. Light curtains can also be used to limit work zones inside the hazardous area and be mounted horizontally for area protection.