-- A refracting telescope must have a lens, otherwise it's not a refracting telescope.
-- A reflecting telescope can be constructed without any lens, but if you intend to
look through it, then you'll use a little lens for the eyepiece.
The part of a telescope were you adjust the size of the lens
The list of choices you included with your question doesn't include any part of atelescope that can do that. I would have picked the objective, whether a lens ora mirror.
The first lens that the light energy passes through on its way through the telescope is called the object lens or the objective. It is the most important and the most expensive part of the telescope. Telescopes are graded by the diameter of the object lens.
A reflecting telescope is different from a refracting telescope because a reflecting telescope uses a concave lens, a plane mirror, and a convex lens. While a refracting telescope uses two lens.
The two lenses on a refracting telescope are typically called the objective lens (at the front of the telescope) and the eyepiece lens (at the back of the telescope). The objective lens gathers and focuses light from distant objects, while the eyepiece lens magnifies the focused image for the viewer.
The "objective" lens (as opposed to the eyepiece).
One end of a reflecting telescope is the big hole pointed at the star. The other end of the reflecting telescope has a lens called an eyepiece.
It is called a refracting telescope.
the hubble telescope is a refracting telescope and it is the biggest one because the refracting telescope can only have a certain range of size for the glass lens because it can only hang on the telescope and it is aproximently 5 meters big the lens. hope it helped
A telescope eyepiece usually has 2 lenses in an astronomical telescope, and it is designed to give a magnified view of the virtual image produced at the focal point of the main lens.
A reflecting telescope has both an eyepiece lens and a mirror. Light enters the telescope and is reflected off the primary mirror to a secondary mirror, which then directs the light to the eyepiece where it is magnified for viewing.
Camera