A Newtonian telescope is a type of telescope that was invented by the English scientist Sir Isaac Newton. The telescope sends an image to the back of the tube and then reflects it off a mirror back up the tube. The image then goes into an angled eyepiece and into the person's eye. The tube usually has many lenses that are used to make the image larger.
- Smith, Warren J., Modern Optical Engineering, McGraw-Hill Inc., 1966, p. 400.