Nadir image taken with the GIFS prototype instrument on board the NASA P3 near Wallops Island, VA, on Feb. 1, 2008. This 400x400-m image of clouds, taken from 21,000 ft, has a spatial resolution of 0.8 m. Concentric circles or rings on the image correspond to different wavelengths of light, with the two dark rings due to molecular oxygen absorption lines near 685 nm. By tuning the interferometer etalons, a sequence of images scans very high-resolution spectral features that contain information about cloud optical properties at every pixel of the image.