Question

A telescope in which the eye lens used is concave, so that the final image is erect, is popularly called a:

Options

• Keplerian telescope

• Binocular

• Cassegrain telescope

• Newtonian telescope

Answer 1

For terrestrial viewing, the final image must be erect. The eye lens used for this purpose must be concave, and such a telescope is popularly called a binocular. The concave eyepiece erects the image while magnifying it.