Photometric observations of auroras were made with the satellite Injun 3 at altitudes of 250 to about 600 km over North America early in 1963. The magnetically oriented satellite simultaneously observed the precipitated electrons which caused the aurora and trapped electrons. The auroral zone, as defined on some fifty latitude surveys of the brightness of the N2+emission at 3914 A, showed an average maximum brightness of about two kilo‐rayleighs at an invariant latitude (Λ) around 69° on the magnetic shellL= 7.8. Several visible auroras are discussed in detail. It is suggested that the auroras delineated the outer edge of the region of durable trapping of Van Allen electrons, and that the electrons causing the auroras and having an isotropic angular distribution over the upper hemisphere at the satellite altitude were mostly freshly accelerated rather than old electrons of the Van Allen belts with similar energy. In two auroras measured by the satellite near perigee, less than 0.1 per cent of the oxygen 5577 A emission came from altitudes above 250 km. Hence the flux of electrons of energy ∼10 ev was no larger than the flux of those with