The Main Ideas : The Telescope And How It Works

The reflecting telescope; from its name, you can easily deduct that this telescope gathers light and reflects it to form an image. This type of telescope uses a mix of curved and flat mirrors.

There are a few parts to the reflecting telescope, the main part being the curved primary mirror that creates the image at the focal plane (Where the image is focused). The focal length is the distance between the mirror and the focal plane. Along the focal length, film and digital sensors could be placed to record the images or an eyepiece to view the images. There is also the secondary mirror, which is placed diagonally and it reflects the light to the focal plane at the side of the telescope tube, another part that's placed under the eyepiece. These are the main parts of the common Newtonian reflector. Other types of reflecting telescopes include the Cassegrain, Nasmyth, Coudé, and Gregorian.

The light reflects off the primary mirror, then focuses on the secondary mirror which in turn sends it to the focal plane. This is how the reflecting telescope works.