Curated OER
Measuring the Sun's Diameter
Students project and measure the suns image using a refracting telescope. In this sun's diameter lesson students calculate the magnification of the telescope and determine the diameter if the Sun.
University of Chicago
University of Chicago: Reflector and Refractor
From the Yerkes Observatory Virtual Tour web site. Compares and contrasts reflecting and refracting telescopes. A link from the page leads to a second page which explains why most modern research telescopes are reflecting telescopes.
Ducksters
Ducksters: Physics for Kids: Telescopes
Kids learn about telescopes in the science of physics including lenses, mirrors, refracting, reflecting, the history, and the Hubble Space Telescope.