Hi. I am new to PF. I am an incoming high schooler with an interest in astrophysics, and a friend and myself are working on building a telescope (not a very sophisticated one, just one that can reveal the craters of the moon and the satellites of Jupiter). I am curious to know if any amateur (or not-so amateur) astronomers have any tips for optical lenses of the telescope. The eyepiece for the telescope will be 4 cm, and the objective lens will be 5 cm. I have considered going online to order eyeglasses, though most sites do not sell the circular, uncut glass without a frame. If I could purchase such a lens, I would not know how to choose a prescription. I do not know how one chooses the desired level of magnification. Does anyone on here have any advice on optical lenses?