What kind of lens is good for a telescope?

Hello: A good astronomical telescope needs good (lens) and large (aperture) composition. It is essential to choose a good astronomical mirror! Take the lens as an example. There are many kinds of objective lenses, the most common one is blue film, and the green film concave-convex objective lens is matched with K and PL eyepieces. The ED objective lens has high imaging, which can be matched with the wide-angle lens of PL eyepieces, so it has a large field of vision and is more comfortable! Aperture is a criterion to determine the capability of a telescope. The maximum effective multiple of a 60-caliber general lens cannot exceed 120 times. It is best to observe below 60 times! The multiple of a telescope is about 1.5-2 times the aperture of this telescope! ~