The multifactorial simulation of assessing the accuracy of modern star catalogues

Abstract

© SGEM2019. This paper focuses on the creation of accurate methods for analyzing star catalogues. The method is based on the multifactorial comparison between coordinates and proper motion from the catalogs studied and the Hipparcos Celestial Reference Frame (HCRF). The HCRF system has been considered the astronomical standard by IAU. Therefore, in this paper HCRF is used for assessing the accuracy of modern star catalogues. The method allows the use of different catalogue epochs at the standard equinox. The stellar digital catalogues (SDC) investigated are as follows: UCAC2 (2004), PPM (1993), Tycho-2 (2000), ACRS (1991), TRC (1998), ACT (1998), FON (2000), Tycho (1997). The method involves several stages. The first stage: the star coordinates from the catalogues are reduced to the J.2000.0 and compared with their analogues from the HCRF system. The second stage: the number (N) of common objects in the catalogue studied and HCRF is determined. The third stage: for each epoch, the absolute values of the differences (n = SDC – N) are calculated. The fourth stage: the percentage of n and N are found. The final stage: the assessment multifactorial model is constructed. The results of the simulations are presented as Lorentzians, according to which one may determine the accuracy of positions and proper motions of the stars in SDC, global external errors, including random and regional ones. The external errors are the ones obtained when reducing the SDC and HCRF systems. As an example, the external errors of the UCAC2 are up to 20 mas for right ascension and 19 mas for declination, for proper motions they are 2 mas/yr and 2 mas/yr respectively.