Why can the High Precisional Observations be Obtained by the LLMC in the Current Conditions

LLMC is a new type of the astrometric instrument.There are some problematic places in the design and the assemblage. The variations in the azimuthal orientation, in the orientation of horizontal axis, in the optical axis, and the assembling errors of the graduation circle and the reading scopes are all beyond the scope of the estimation. In spite of the current conditions, all kinds of instrumental errors are measured and corrected in real time, furthermore, all sources of the systematic errors from the instrument itself and in the measuring of errors are avoided. All the observations are carried out at any moments relative to the plumb line and to the direction of the instant rotation axis of the earth. Therefore, high precisional observations can be obtained.