parallax difference
1.This paper introduces the formation and changes of diurnal aberration and annual aberration and compares in simple language the difference of directions between annual aberration and annual parallax and the difference of time when extremes emerge. Besides, it introduces the means of determining aberration of light and points out that it is impossible at present to determine aberration of light caused by the absolute movement of the earth.
2.Trigonometric parallaxes determined separately in right ascension and declination, π_x and π_y, are analyzed based on the parallax data published so far by the Royal Greenwich Observatory, U. K. The results show that there appears to be a significant correlation between difference π_x-π_y and right ascension α.
