Measurements of tilt angular anisoplanatism

A new approach for the experimental study of tilt angular anisoplanatism is developed. This method uses measurements of the random motion of a moon edge image to assess wavefront tilt. This technique provides a wide, continuous range of angular separations which are not available in observations of binary stars. It is determined that the brightness of the moon is sufficient to make observations with a high resolution imaging system. Statistical properties of the tilt angular correlation and tilt averaging function are experimentally investigated. It is shown that tilt angular correlation scale increases from 40 arcsec to 118 arcsec by increasing telescope diameter, indicating that the concept of isoplanatic angle is not applicable to tilt-related phenomena.