The ESA Gaia space astrometry mission will perform an all-sky survey of stellar objects complete in the nominal magnitude range G = [ 6.0 - 20.0 ] .
The stars with G < 6.0 , i.e .
those visible to the unaided human eye , would thus not be observed by Gaia .
We present an algorithm configuration for the Gaia on-board autonomous object observation system that makes it possible to observe very bright stars with G = [ 2.0-6.0 ) .
Its performance has been tested during the in-orbit commissioning phase achieving an observation completeness of \sim 94 \% at G = 3 – 5.7 and \sim 75 \% at G = 2 – 3 .
Furthermore , two targeted observation techniques for data acquisition of stars brighter than G =2.0 were tested .
The capabilities of these two techniques and the results of the in-flight tests are presented .
Although the astrometric performance for stars with G < 6.0 has yet to be established , it is clear that several science cases will benefit from the results of the work presented here .