Complete Guide on Parts of Telescope: Names, Functions & Diagram

Overview of Telescope Anatomy

As we know, the telescope is one of the important optical instruments for Astronomical scientists. It consists of different telescope parts like lenses, eyepiece, finderscope, etc. Without it, we can’t see the universe beyond our earth. With the help of a telescope, today’s scientist finds a new planet, universe, & threats to the earth. Before handling it we have to know the parts of a telescope.

Diagram of Telescope Parts

Parts of a Telescope, Names & Diagram

Parts of a Telescope Names

  • Lenses
  • Mirror
  • Structural support or tripod
  • Eyepiece
  • Telescopic Tube
  • Finderscope

Telescope Parts


The lens is one of the necessary parts of a telescope. In most refracting telescopes, there are two lenses in which is the objective lens, and the other is the eyepiece lens. The bigger lens is an objective lens, while the smaller lens is an eyepiece lens.

The objective lens is convex, while the eyepiece lens is concave in shape. The objective lens is at the front side to focus on the image, and the eyepiece lens is at the backside of the telescope for magnification.


Mostly all telescopes have two mirrors. Depending upon design consideration, the shape of the mirror can be plane, parabolic, or hyperbolic.

These two mirrors are called primary and secondary mirrors. The primary curved mirror forms an objective, while the secondary curved mirror is placed at the focus of the first mirror inside the telescope body.

Structural Support / Tripod

As we know, high-power telescopes are huge and difficult to handle with our hands. So that it mounts on the robust structures & can move on the horizontal and vertical axis.

This telescope is highly efficient and very easy to handle. For some handheld telescopes, a tripod is used as structural support.


The eyepiece is the part of a telescope by which we can see our specific object. The function of the eyepiece is to magnify the image that we must view. The eyepiece comes with different focal lengths.

Generally, the magnification of the telescope can be calculated by the ratio of the focal length of the objective lens to the focal length of the eyepiece lens. In final words, the smaller the focal length higher the magnification power.

Magnification Power = Focal Length of Objective lens / Focal Length of Eyepiece lens.

Telescopic Tube

A telescopic tube is the body of any telescope which contains a primary mirror. Generally, the diameter of the telescope is about 8 inches. It improves its focal length by just adjusting the knob.


Finderscope is not an essential but an important part of a telescope. It is nothing but a small telescope attached to the main telescope of the body. It is pointed in the same direction as a telescope.

The function of a finderscope is to find approximately the location of the object or place where we must be viewed. This finderscope has a small magnitude and a wider field of view.

The design specification of the finderscope is 6 x30, where 6 is the magnification power & 30 is the aperture in millimeters.

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