Abstract: A usable golf ball including an on-demand illuminating device embedded therein that is activated by exposure to external light impulses is provided. Such an illuminating device includes a photocell securely and safely positioned within the subject golf ball core in a suitable manner to allow for uniform weight displacement therein. Additionally, the device includes a switch that operates in response to light impulses wherein an initial light impulse exposure turns the photocell on and a subsequent light impulse exposure deactivates the photocell. With a properly configured illuminatable dimpled ball surface material, the resultant ball will thus illuminate on demand to permit a distinct aesthetically pleasing and/or recognizable iridescent color therefore. Such a golf ball thus includes at least one surface window structure to permit such light impulse exposure externally by the user that leads inward directly to the device switch.