N－Cat系列综合河外射电源表

本文利用弧长差选源方法和共同基本源指向维持模型，并参照当今各河外射电源观测表之间的相互独立性，组建了１９８８至１９９３各年度的综合河外射电源表，即Ｎ－Ｃａｔ系列综合表。检验结果表明，Ｎ－Ｃａｔ系列表中坐标系是统一的，其指向维持精度高于０．１ｍａｓ，明显好于Ａ－Ｃａｔ系列表和ＩＥＲＳ系列表，这充分肯定了弧长差选源方法和共同基本源指向维持模型的优越性。文中部分结果显示，１９９２年与１９９３年的ＩＥＲＳ综合表之间存在显著指向差异，对此应予以重视。

N-Cat Series Combined Extragalactic Radio Source Catalogues

The N-Cat series combined extragalactic radio source catalogues were compiled on the bases of the Are Length Difference primary source selection method and the Common Primary Source orientation maintenance model, and by referenee to the correlations among individual catalogues. Tests show that the Arc Length Differenee selection method can highlight the individuality of every source on the basis of consistence of all sourees and can be adapted to the improvement in the accuracy of observation catalogues, the sky coverage and so on.It is relatively an objective selection method. Calculations show that the Common Primary Source orientation maintenance model is more desirable than the IERS one, which was on the base of all primary sourees of a version of the frame, in the consideration of orientation stability for a long time span.Results from examinations show that the coordinates in the N-Cat series catalogues are in consistence, and that the stability of the orientation is better than 0. 1mas, which is superior to the A-Cat series catalogues as well as the IERS combined catalogues. Some results also show that the orientation of the IERS combined catalogues in 1992 and 1993 did not coincide with each other very well, some attention should be paid for this point.