Eyes on the Infinite: The Telescope Instruments Quiz

If Earth's atmosphere contains gas and dust, then light passing through it becomes distorted or "twinkles"; if a telescope is placed in space above the atmosphere, then the light reaches the sensors without distortion, resulting in a clearer image.

If scientists need to identify the chemical elements in a star, then they must look at specific wavelengths of light; if a spectrograph spreads light into a spectrum, then the resulting dark lines reveal the star's chemical makeup.

If radio waves have much longer wavelengths than visible light, then they can pass through clouds and atmosphere without being scattered; if the sun's visible light does not interfere with radio signals, then these telescopes can operate 24/7.

If a star is much brighter than the planets orbiting it, then the glare hides the planets; if a coronagraph blocks the direct light from the star, then the much fainter nearby objects become visible to the camera.

If infrared telescopes detect heat energy, and if the telescope itself is warm, then the instrument's own heat will glow and drown out faint signals from space; if the telescope is kept extremely cold, then it can detect the faint heat of distant galaxies.

If a telescope uses a lens to bend light, it is a refractor; if it uses a curved mirror to bounce light to a focal point, then it is classified as a reflecting telescope.

If Earth's atmosphere causes light to shimmer, then images become blurry; if adaptive optics uses a computer-controlled flexible mirror to counteract these ripples in real-time, then the resulting image becomes nearly as sharp as one from space.

If Earth's atmosphere is thick enough to block high-energy X-rays from reaching the ground, then sensors on the surface cannot detect them; if we want to see X-ray sources, then the telescope must be positioned above the atmosphere in space.

If an astronomer needs to track how a star's brightness changes over time, then they need a tool to count photons; if a photometer measures the intensity of light over time, then it can help discover planets as they pass in front of stars.

If radio waves are very large and spread out, then a small collector won't catch many; if a giant dish provides a large surface area to reflect these waves into a single receiver, then the signal becomes strong enough to analyze.

If a telescope has multiple mirrors, then the first and largest one that encounters the incoming light is the most important for gathering light; if it is the first in the sequence, then it is the primary mirror.

If the atmosphere is thinner at high altitudes, then there is less air, dust, and water vapor to distort light; if a telescope is placed on a mountain, then it looks through less "air," resulting in better data than at sea level.

If a telescope on Earth breaks, then technicians can drive to it with tools; if a telescope is in high Earth orbit or a million miles away, then sending a repair mission is extremely difficult and expensive.

If water vapor absorbs specific wavelengths of heat energy, then those signals cannot reach the ground; if infrared is heat energy, then high-altitude or space telescopes are required to see it clearly.

If an astronomer wants to save and analyze an image on a computer, then the light must be converted into an electronic signal; if a CCD is a light-sensitive silicon chip that does this, then it is the digital "film" of the telescope.

If light passes through pockets of air with different temperatures and densities, then the light path bends rapidly; if this bending causes the star's position and brightness to appear to shift, then the effect is known as scintillation.

If launching a rocket into space is very expensive, and if batteries and parts cannot be easily replaced, then space telescopes have high costs and limited operational lives compared to ground-based ones.

If the resolution of a telescope depends on the size of its collector, but building one giant mirror is impossible, then we can link smaller telescopes together; if their signals are combined precisely, then they achieve the detail of a much larger instrument.

If city lights scatter into the atmosphere, then the background of the night sky glows; if the background is bright, then the faint light from distant stars and galaxies is "washed out" and cannot be detected.

If the primary mirror reflects light back up the tube, then the light needs to be directed to a camera or eyepiece; if a secondary mirror is placed in the path, then it bounces that light to a convenient exit point for the instruments.