Realistic long path high resolution transmission spectra of the atmosphere have been calculated in the regions of the (0,0) and (1,0) NO gamma bands for zenith angles between 40 and 70° and for path lengths between 28.5 and 120 km. The transmission spectra have been folded onto the Harvard solar rocket spectra to provide spectral irradiances at 28.5 km which is a typical balloon float altitude. Such data have immediate application to the remote sensing of atmospheric NO from balloons and satellites.