Influence of Solar Granulation Characteristics on Correlation Tracker of Space Solar Telescope

To research the influence of solar characteristics on space solar telescope (SST)'s correlation tracker, the observed data of the solar optical telescope (SOT) aboard the Hinode satellite was used, the correlation calculation for five images with sampling interval time of 2 minutes was implemented, and the evolution of solar granulation with time was found. For the correlation tracker image stabilization system of SST being developed in the National Astronomical Observatories, Chinese Academy of Sciences, the influences of granulation evolution on calculation accuracy of image movement of the correlation tracker system and telescope exposure time were analyzed. The results indicate that the time to replace the reference image should not longer than 2 minutes. By comparing the correlation coefficient of the images with different sizes, it is found that using larger reference images could improve the positioning accuracy of the correlation tracking system. This research could provide some advices for the development of the correlation tracker system of SST.