Hi all, I am implementing a lab activity for a 2 lens set-up that will serve as a simple telescope. In the teacher's manual, it lists down 2 plano-convex lenses, with the 2 curved surfaces facing each other. The plane faces will respectively face the light source and the observer's eye. A simple net search shows that regardless of which side (i.e. plane or curved) of the planoconvex lens is facing the light source, the point of convergence of the light rays will be the same on the opposite side of the lens. Which then begs the following 2 questions, what then is the key difference(s) between a plano-convex lens and a biconvex lens? Will my 'telescope' fail to work if i use 2 biconvex lens instead? Thanks in advance. Physics Forums rock!