Objectives:
To acquaint experimental scientists with the NETM axioms, features and areas of its use, the results of checking the adequacy of its postulates at the Main Astronomical Observatory of the Academy of Sciences of Ukraine.

Material and methods:
Probability and mathematical-statistical procedures are used in the NETM, which ensure the effectiveness of estimations of the studied parameters and diagnostics of mathematical modeling.

Results:
The justified necessity of applying the new error law with the volumes of samples n > 500, in accordance with the recommendations of professor of the University of Cambridge H. Jeffreys.

Conclusions:
The Non-clasical Error Theory, which was created at the Faculty of Cybernetics of the Academician Stepan Demianchuk International University of Economics and Humanitiesr in 2015, has passed many years of testing and proved its effectiveness in the mathematical processing of modern scientific and technical measuring experiments of a large volume. The use of the NETM in the analysis of data allows solving three important problems, namely: 1). Use modern, adequate representation of the error distribution law of observations of large volumes. 2). Obtain effective estimates of the fundamental distribution of the NETM - the Pearson-Jeffreys law and its most important characteristic - the parameter m, which is a measure of the deviation of the statistical distribution from the Gauss law and is the main metrological characteristic of the observation method. 3). Solve the problem of weighing abnormal errors.