Specialized lighting fixtures, such as for theaters, museums, galleries, exhibits, etc. frequently employ accessory elements, such as color filters, conditioners, beam spreading or concentrating lenses, and the like to achieve desired lighting effects. In many such circumstances, it is necessary or desirable to change the accessories from time to time to accommodate changes in the lighting requirements. As set forth in a related U.S. Pat. No. 6,942,368, to Kenneth M. Kane et al, it is advantageous to utilize a removable cartridge to hold the desired accessories. This allows the accessories to be installed in a cartridge in the proper order, at a work bench or other convenient location, after which the cartridge can be quickly and easily inserted into the lighting fixture. This minimizes the time and effort required of a service man while working high on a ladder.
Inasmuch as a given lighting fixture may typically utilize from one to three accessories, and occasionally none, there was a need to be able to optimally position the accessories with respect to the light source, in order to enhance the efficiency of the lighting and the effectiveness of the accessories.