A careful observer with normal equipment is quite capable of obtaining nightly measures that are consistent to within a few tenths of a second of arc.

• 如果观测者打算在上报前核对已知天体的测量误差，我们在取舍数据的时候尽量考虑到误差的一直性（尤其是多晚的数据），而不仅仅考虑偏差的多少。