The operational TIROS/NOAA satellites deployed by the United States transmit multiplexed imagery that includes (in daylight) simultaneous visible and infra-red (IR) image data. Here is a summertime NOAA pass over western North America, stretching from northern Mexico in the south to southern Canada in the north. Visible light data are shown in the left frame while IR data appear to the right. The image was acquired in Michigan with an omni-directional quadrifilar helix antenna and the Quorum Communications Wefax Explorer system - an imaging card for the PC that includes the satellite receiver electronics. The original image has been degraded in resolution by a factor of about eight to fit the page. To see the images in greater detail, click on NOAA IR for the infra-red (right) view or on NOAA VIS for the visible light (left) view.