Mirrors or Lenses? The Ultimate Telescope Types Quiz

If we look at the history of astronomy, then we see Galileo was the first to point a lens-based (refracting) telescope at Jupiter. If Newton is mentioned, then he is associated with the invention of the reflecting telescope.

If a lens is very large, then it can only be supported by its edges. If it is too heavy, then gravity pulls on the glass and distorts the image. Mirrors can be supported from the back, so they don't sag.

If a telescope captures light, then that light must be magnified for the human eye. If the "eyepiece" is the final lens in the system, then that is where the observer places their eye to see the image.

If a surface is shiny and polished like a mirror, then light cannot pass through it. If the light hits that surface, then it must reflect (bounce) back in the opposite direction.

If a reflecting telescope uses a mirror to bounce light back and forth inside the tube, then the tube can be shorter. If a refracting telescope needs a long path for the light to bend, then the tube must be very long.

If the lens is at the front "object" side of the telescope, then it is called the objective lens. If it were a mirror at the back, then it would be the primary mirror.

If a telescope is made for home use, then it is designed to be lightweight. If a refracting telescope has a small lens and a thin tube, then it is the most portable option for a student.

If the Hubble needs to be very powerful and fit inside a rocket, then it must use mirrors to save space and weight. If it uses a large 2.4-meter mirror to catch light, then it is a reflecting telescope.

If you want to see dim objects, then you need to catch as many "light buckets" as possible. If the lens or mirror is wider (larger aperture), then it collects more light, making dim things visible.

If a telescope is a reflecting type, then it must use a mirror to bounce light. If the goal is to gather light, then the primary mirror at the bottom of the tube performs this task.

If light enters the tube, then it must travel to a surface that reflects it back up. If the primary mirror is at the bottom, then it can catch all the light and send it toward the secondary mirror.

If light moves from air into glass, then it changes speed. If the light changes speed at an angle, then it bends. This specific process of bending light through a medium is defined as refraction.

If a lens bends light, then different colors of light (like red and blue) bend at slightly different angles. If they don't meet at the exact same spot, then you see a rainbow-like blur called chromatic aberration.

If Newton noticed that lenses created color fringes (chromatic aberration), then he sought a way to gather light without bending it through glass. If he used a mirror to reflect light instead, then the color blur disappeared.

If a telescope does not contain any mirrors and relies solely on glass pieces to guide light, then it is classified as a refracting telescope.

If the main lens or mirror gathers the light, then the image is still very small. If you add a smaller lens called the eyepiece at the end, then it acts like a magnifying glass for your eye.

If the big mirror sends light back up the tube, then it would hit the observer's head. If a small "secondary" mirror is placed in the path, then it can kick the light out to the side for the eyepiece.

If the image looks blurry, then the light rays are not meeting exactly at your eye. If you move the eyepiece back and forth, then you find the "sweet spot" where the light focuses perfectly.

If the telescope is a refracting type, then it relies on the principle of refraction. If light passes through a curved piece of glass (a lens), then the light bends to a focal point.

If the telescope is a "reflecting" type, then it uses reflection (mirrors). If a lens is used to collect the light instead, then the telescope is a "refracting" type, making the statement false.