Sky And Telescope Magazine
This informative site will answer your questions about current events in the heavens and equipment for new and advanced amateur astronomers. Perhaps of greatest value is access into over 60 years of articles in "Sky & Telescope."
The Magic Mirror of Life by Jack & Beverly Wilgus
This site traces the development of camera obscuras from the earliest pinhole devices to modern operating instruments with motorized mirrors and lenses. Portable and handheld units used by artists are fully illustrated as well.