Ray-tracing of a Keplerian telescope

[Opera Laboratori Fiorentini]

These two Plexiglas lens sections represent the optical structure of a Keplerian telescope. Both the objective and the ocular are bi-convex. The five parallel rays of the light source converge at the focus of the objective, and then they become again parallel beyond the ocular. However, since the rays cross at the focus, the image formed is upside down. One can interrupt the rays to understand the implications that such action has on the image making.

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