University of Maryland
Optics Highlights: The Telescope
Part of an anecdotal history of optics and the study of light. Extremely thorough treatment of the invention of the telescope. Includes a short biographical sketch and discusses the work of Isaac Newton which focuses on his contribution...
TryEngineering
Try Engineering: Telescoping Periscope
Working in teams of "engineers", students explore how a periscope works and is used. They design, build, and test a working periscope made from everyday materials that has adjustable mirrors and be able to telescope as well.
Walter Fendt
Walter Fendt: Refracting Astronomical Telescope
An app for investigating the operation of a refracting telescope. The location of the eyepiece and objective lens can be altered, and the focal point and path of light through the lenses can be observed.