This is a friend's favorite question for the first time. The answer is infinity. Actually, the real intention of this question is to ask the telescope how to distinguish it. This involves three factors:
1, how to observe the environment, including intensity and direction of light, contrast, atmospheric stability and transparency.
2, the quality of the telescope itself, including specifications, categories, accuracy and so on.
3. The vision condition of the observers after correction and the degree of proficiency in the use of binoculars.
These 3 aspects are basically uncertain. If only the ability of the telescope itself is taken into account, the telescope with a larger diameter and a higher number of binoculars is generally higher, and the Porro prism telescope has a higher resolution than the roof prism telescope, and the coated mirror has a higher resolution. It should be emphasized that the multiplier of telescope is only one of the many factors that affect resolution. It is not desirable to blindly pursue large multiple.