One of the biggest limitations of Galilean telescopes, with their combination of a convex and concave lens, was their narrow field of view. Galileo used them to survey the lunar surface ...

Instead of a concave lens near the eye ... Kepler's advance created a new challenge, however. Because his telescope offered a much greater field of view, astronomers had plenty of room to improve ...

Draw a ray which passes from the object through the centre of the lens. Some ray diagrams may also show a third ray. Peep holes contain concave lenses. They are set into doors so the occupant can ...

Save guides, add subjects and pick up where you left off with your BBC account. Convex and concave lenses can both be used to correct defects of vision. The most commonly occurring defects of ...