Fast large aperture photometers directed at the zenith on clear nights near Minneapolis have recorded many light pulses in the millisecond time range, but aside from man-made events these were almost entirely due to Rayleigh scattered distant lightning, with a residual very low rate (<0.1/hr) of unidentified pulses. We believe that 1 ms light pulses seen in several previous experiments (FAP's) may also be mostly Rayleigh scattered lightning, rather than fluorescent light due to electron precipitation from lightning-induced whistlers as previously discussed. ¿ American Geophysical Union 1989