The observational program and research tests of an automatic PZT with prolonged exposure

The theory and instrumentation of the PZT have been described by several authors. In comparison to other techniques available for the determination of Earth Rotation Parameters (ERP), the PZT has many advantages. Among these are its rigid construction, elimination of levelling errors, minimization of refraction errors, ease of operation, etc. Among the disadvantages of a PZT are its limited field of view by which few stars can be observed.