Astronomical telescopes usually have two telescopes, the big one is the primary mirror, which is used to observe the target; the small one is called the star-seeking mirror, which is used to find the target, also known as the sight. The eyepiece is a single individual, it is the object that decides the magnification. There will be F value on the eyepiece. This is the focal length of the eyepiece. Dividing the F value of the primary eyepiece by the F value of the current eyepiece is the current magnification. Remember, the magnification rate is the standard. The limit magnification of a 6 cm telescope is about 120 times and that of an 8 cm telescope. The maximum rate is about 160 times.