Refracting telescope. Refracting telescope The Galilean telescope The objective lens, whose focal length is f, performs the same function. - ppt video online download
Essential Optics Review for the Boards: 28
Notes about Keplerian 'expanded field' telescopes. - Ocutech
History of Science Society -- Committee on Education
Understanding the Different Bioptic Telescopes - From Ocutech
Galilean and Keplerian telescopes - American Academy of Ophthalmology
Understanding the Different Bioptic Telescopes - From Ocutech