To reduce distortions such as elongations and blurriness caused by the curvature of the "objective" lens—the convex lens at the far end of the telescope—Galileo ground a lens larger than he ...

It has a single eyepiece, like a telescope, and an objective lens, but in between is a prism to correct the orientation of the image. The main differences between a telescope and a monocular are ...

It uses focused light passed through the object and two lenses to magnify an image of the object. If looking at an object under the ×4 objective lens, light will have passed through the object ...

If you're keen on dual-purpose 'bins' for daytime birdwatching and moongazing, consider ones with large light-gathering objective lenses. Our current number one binocular is Celestron's Nature DX ...