Abstract: A high mast lighting structure including a hollow mast and a light and reflector or illumination assembly adapted to be raised to the top of the mast by operation of a hoisting cable secured to the assembly. A plurality of latch-type locking and support means are positioned between the illumination assembly and a support plate secured at the top of the mast. Each locking and support means includes a first member mounted to the illumination assembly and comprising a pair of generally planar, oppositely facing spring-loaded bracket or jaw portions which normally rest in substantially parallel position. A second member of each locking and support means comprises a bayonet-like projection having outstanding cam surfaces; the second members are mounted to to the support plate.