Mirror, Mirror: Reflecting Telescopes Explained Quiz

If a telescope is designed to "reflect" light rather than "refract" it, and if mirrors are the objects that reflect light, then the primary light-gathering tool must be a mirror.

If the main mirror is at the bottom of the tube and bounces light back toward the opening, and if the observer needs to see that light without blocking the tube with their head, then a second mirror is required to redirect the light to an eyepiece.

If the primary mirror is at the back of the telescope, and if the purpose of a mirror is to reflect, then the light must hit that mirror and travel back up the tube toward a focus point.

If a telescope has two mirrors and the largest one is responsible for the first stage of light collection, then that most important mirror is defined as the primary mirror.

If a glass lens is very heavy, it can only be held by its edges and will bend under its own weight; if a mirror can be supported across its entire back surface, then it can be built much larger without distorting the image.

If the first successful telescope to use a mirror instead of a lens was built in 1668 to solve the problem of rainbow-colored blurry edges, and if Isaac Newton was the inventor of that design, then he is the correct scientist.

If the goal is to bring light rays together (converge) to a single point, and if a bowl-shaped surface bounces light toward the center, then a concave shape is necessary for the mirror to focus light.

If we are describing the physical behavior of light hitting a shiny surface and returning in a different direction, then the scientific term for that action is reflection.

If a reflector uses mirrors to bounce light to an eye, then it needs two mirrors and an eyepiece; if it is a reflector, it does not use a large objective lens at the front.

If light passes through glass (lenses), different colors bend at different angles and fail to meet at one point; if light bounces off a mirror instead, all colors reflect at the exact same angle, preventing the rainbow blur.

If the Hubble telescope is a Cassegrain reflector, and if that design relies on a 2.4-meter primary mirror to capture images of galaxies, then it is a reflecting telescope.

If a mirror is perfectly curved to ensure every light ray meets at the exact same location for a sharp image, then that specific meeting spot is called the focal point.

If the secondary mirror is tilted at a 45-degree angle to send light out the side of the telescope, and if the observer needs to look through it, then the eyepiece must be mounted on the side of the tube.

If a mirror is the "light bucket" of the telescope, then size and smoothness determine how many photons are caught and how clearly they are organized; if the shape is correct, the image will be sharp.

If glass by itself is transparent and lets light through, and if we want it to act as a mirror, then we must apply a highly reflective metallic coating to ensure the light bounces off the surface.

If professional telescopes need to be compact but have long focal lengths, and if the Cassegrain design folds the light path back through the center of the mirror, then this design is the standard for large observatories.

If we measure the physical space light travels between the reflective surface and the image it creates, then that measurement is defined as the focal length.

If magnification is calculated by dividing the telescope's focal length by the eyepiece's focal length, and if the number on the bottom (the divisor) gets smaller, then the resulting magnification value must get larger.

If mirrors avoid the physics of light-bending through glass and can be supported easily from underneath, then they are ideal for large-scale astronomy; however, they cannot see through clouds and are not always cheaper.

If a large lens must be thick to work, and if a mirror only needs a thin shiny surface to reflect light, then a mirror of the same diameter will be much lighter and easier for a telescope structure to hold.