The first telescopes, known as refracting telescopes, were built in the early 17th century by Dutch eyeglass makers. They employed a pair of lenses—one convex fitted at the end of the scope, and one ...

For most of us who are not astronomers, the image that comes to mind when describing a reflecting telescope is of a huge instrument in its own domed-roof building on a mountain top. But a reflecting ...

IIIF provides researchers rich metadata and media viewing options for comparison of works across cultural heritage collections. Visit the IIIF page to learn more. This is the original infrared ...