the use of these high efficiency high output leds has the specific advantage that the number of leds may be relatively small for a desired relatively high light output this contributes to the compactness and efficiency of the luminaire to be manufactured in an alternative embodiment u201c prometheus u201d type leds hewlett packard are used as the high efficiency high output leds the luminous flux per led being 35 lm for the red leds and 30 lm for the green leds by using one or more high efficiency high output leds as the light source luminaires are obtained which are daylight viewable and whose brightness is comparable to that of the known luminaire preferably the led 3 is mounted on a metal core printed circuit board 13 preferably the metal core printed circuit board 13 is in contact with the metal housing 1 provided with cooling fins 11 via a heat conducting connection such a heat conducting connection is preferably brought about by connecting the mc pcb 13 to the metal housing 1 either directly or via a metal plate the heat generated in the led or leds 3 can be dissipated by thermal conduction via the mc pcb 13 to the housing 1 and the cooling fins 11 in which process heat dissipation to the environment takes place this has the advantage that forced air cooling for dissipating heat as employed in the known luminaire is not necessary the optical system 4.