Question

What is the difference between cassegrain and newtonian telescope
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Answer 1

Larger reflecting telescopes use something known as aCassegrain focus. A Cassegrain telescope is a kind of reflectingtelescope where a secondary mirror reflects light back through a hole in the primary mirror's center. ... So, the big difference between the Cassegrain and Newtonian telescope should be quite obvious.

Answer 2

The Newtonian telescope is a kind of reflecting telescope that uses a diagonal mirror to reflect light out the side of the telescope. Thus, the eyepiece is positioned at the side of the telescope. This design is usually used in smaller telescopes.

Let's go over the diagram of a Newtonian telescope below to see what happens.

First, light enters from the left and hits the primary mirror at the back of the telescope. A focused image is then bounced off of a secondary mirror, through an eyepiece, and to the observer's eye. The secondary mirror is a type of mirror used in a reflecting telescope that directs light coming from the primary mirror to another focal point.

The Cassegrain Telescope

Larger reflecting telescopes use something known as a Cassegrain focus. A Cassegrain telescope is a kind of reflecting telescope where a secondary mirror reflects light back through a hole in the primary mirror's center.

Again, let's take a look at the image below to see what happens here.

First, light comes into the telescope from the left. It will, as usual, bounce off of the primary mirror. Then it will hit the secondary mirror, and from there it will travel through a central hole in the primary mirror where there's an eyepiece or a detector. The hole in the center of the primary mirror is called an aperture.

So, the big difference between the Cassegrain and Newtonian telescope should be quite obvious. The light rays are reflected to an eyepiece that's at the back of the telescope in the former instead of the side of the telescope as in the case of the latter.