The 66942 Research Mercury Arc Source is a fully featured arc source compatible with Oriel's LIK-LMP Light Intensity Control System for long term output stability, and interchangeable 200 to 500 W Hg lamps. The housing with a 1.5 Inch Series flange provides a temperature controlled, stable environment for the lamp, and protects personnel from the harmful UV radiation emitted. A number of safety features are incorporated into the housing to prevent accidental exposure and lamp overheating. It also houses the ignitor and collimating lens assembly. A socket adapter holds the lamp, vertically, in the center of the lamp housing. To switch between lamps, you must change socket adapters. External adjustment knobs allow lamp centering. A reflector mounted behind the lamp collects the lamp's back radiation and redirects it to the condenser, maximizing output. The 66942 has a F/1, two element fused silica condenser assembly including a lens element(s) inside a barrel housing with a locking focusing lever. This condenser is designed to produce a 1.3 inch (33 mm) collimated beam, but the focusing lever lets you adjust the lens position to produce a converging or diverging beam. The OPS-A500 is included and operates any of the specified lamps under extremely tight power or current control. The source also includes your choice of lamp and all necessary cables, sockets and mounting hardware. Please specify your lamp choice at time of order.