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 ...

The new 100-millimeter (3.9-inch) diameter lens, which has a 200 mm (7.8 in) focal length, is just 2.4 micrometers thick. Optimized for the 400 to 800 nm wavelength range for visible light, this ...

The space telescope's image of a odd-looking spiral galaxy is, in reality, two distant galaxies overlapping each other.

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 ...

Convex and concave lenses can both be used to correct defects of vision. The most commonly occurring defects of vision are ‘short sightedness’ and ‘long sightedness’. People who are ...