Which type of telescope uses a convex lens to increase the size image being viewed?

The type of telescope that uses a convex lens to increase the size of the image being viewed is called a refracting telescope.

Here's why:

* Refracting telescopes use a convex lens (also known as a converging lens) as their primary objective lens. This lens bends the light rays coming from a distant object and brings them to a focus, creating an image.

* Reflecting telescopes, on the other hand, use a concave mirror to gather and focus light.

So, the key difference lies in the primary light-gathering element: a convex lens for refracting telescopes and a concave mirror for reflecting telescopes.