【摘要】 本文利用美国海军天文台和Van Vleck天文台发表的资料,对赤经、赤纬方向所确定的恒星三角视差作了讨论,发现对于这两个台站,差数△π=π_x-π_y的绝对值随赤经α表现有十分类似的周期性的变化.分析表明这种变化是由π_y的误差引起的,并且与目前视差测定一般保证有最大赤经视差因子的做法有关.因此有条件时应增加使赤纬视差因子为极大的观测资料.更多还原

【Abstract】 The trigonometric parallax data in both α and δ directions published at USNO and Van Vleck Observatory are in some detail analyzed statistically. Some obvious evidences are found to show that tbe absolute values of differences between π_x and π_y determined separately in right ascension and declination vary statistically with right ascension of stars, the variation being very similar for both observatories. Furthermore, the quantities σ=, where σ_x and σ_y are the mean errors corresponding to π_x and π_y respectively, also display some variation with right ascension of stars, which is not only similar for both observatories, but also very similar to that of |π_x-π_y|. The same regularity of variation was found for the small sample of the parallax data of RGO. We suggest from a detailed analysis that the variation mentioned above is caused by the errors of π_y. Since the general program for parallax determination used currently at present is to make the parallax factor right ascension as great as possible, which must lead to the errors of π_y being maximum around α=6h or 18h. So it will improve the accuracy of determination of parallaxes to add, if possible, some observations at proper dates in order to obtain as great parallax factor in declination as possible as well.更多还原