Accurate, detailed maps of total ozone were not available until the launch of the Total Ozone Mapping Spectrometer (TOMS) in late 1978. However, the Scanning Radiometer (SR) on NOAA satellites during the 1970s included a visible channel that overlapped closely with the Chappuis absorption band of ozone around 600 nm. We use a simple calculation of two-way transmittance to obtain total ozone from data taken by the Advanced Very High Resolution Radiometer (AVHRR). THe AVHRR was the successor to the SR on NOAA satellites, and because it flew during the 1980s, we are able to compare our derived ozone amounts with those derived from TOMS. Our method works only over scenes whose albedos are large and unvarying.