The High Altitude Observatory (HAO) is committed to providing the highest quality observational coronal data and making these observations available to the Solar Physics Community. The recent solar pass by Ulysses and the launch of the Solar and Heliospheric Observatory (SOHO) enhance the importance of quality observations of the low corona.
HAO plans to build and deploy a next generation coronal observing system at the Mauna Loa Solar Observatory (MLSO). Before constructing a new instrument for K-corona observations, a project was started to evaluate the quality of current MkIII K-coronameter observations. The MkIII records images of the K-corona daily, and has been in operation since 1980 [ Fisher et al., 1981]. Since the start of that project, much progress has been made in computer technology and in the understanding of polarimeter calibration. These advances, coupled with changes in the personnel associated with the MkIII, made it necessary to review the calibration techniques, routine calibration of data, quality verification and instrument performance.