Optical Observations of Time and Latitude and the Determining of the Earth’s Rotation Parameters in 1980

Abstract

This paper is based on optical observations of 85 instruments (Table 1-a) from January to October 1980. The accuracies of all instruments, 62 for time and 54 for latitude, are shown in Table 1-b, in which :

• the roughness ε_li of daily observations is defined by the standard deviation of the observation values of the i-th instrument with respect to the smoothed values of themselves;

• the ε_2i is the standard deviation of mean observation values during every 0.05 year with respect to the global reference system.