Telescopes Trivia
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59 free Telescopes trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Telescopes have been rewriting our picture of the universe for a little over four centuries. This quiz follows the whole story: the 1608 patent application by a Middelburg spectacle-maker, Galileo's leaden tube and the banquet where the word 'telescope' was coined, Kepler's improvement, Newton's first working reflector and the tarnishing metal mirrors that plagued astronomers for 200 years, the achromatic lens, the great refractors that ended with Yerkes, Herschel's forty-footer and the Leviathan of Parsonstown, then the mirror giants: Hooker, Hale, Keck, the Very Large Telescope and the 39-metre Extremely Large Telescope now rising in Chile. It also covers the other kinds of telescope: Jansky's merry-go-round and Grote Reber's backyard dish that started radio astronomy, Arecibo and China's FAST, the Event Horizon Telescope that photographed a black hole, and the space observatories from Hubble and Chandra to Kepler and James Webb. Easy questions ask what the two basic optical designs are and what the word means in Greek; harder ones get into speculum metal, Wolter mirrors, Ritchey–Chrétien optics and why nobody builds refractors bigger than a metre. It suits astronomy students, amateur observers, science teachers and quiz nights. Fans of Hubble specifically will also find our dedicated Hubble Space Telescope quiz. Every answer has been checked against the Wikipedia articles on telescopes, their history and the individual instruments named, and each question shows its source once you have answered.
30 of 59 questions with answers and explanations. Play the quiz
Q 01From which language do the roots of the word 'telescope' come, meaning 'far' and 'to look'?
Greek
Greek. Tele means 'far' and skopos 'watcher'; the name is said to have been coined in 1611 at Rome's Lincean Academy, for an instrument its new member Galileo was showing.
Q 02Galileo's telescope revealed four moons circling which planet in January 1610?
Jupiter
Jupiter. Galileo first took the points of light beside it for fixed stars, then saw that they had moved by the next night and concluded they were circling the planet.
Q 03Edwin Hubble showed in the 1920s that other galaxies exist after spotting a pulsing star in which one?
The Andromeda Galaxy
The Andromeda Galaxy. On photographs from the 100-inch telescope, Hubble found a star whose steady pulsing gave away its distance, far too great for it to lie inside the Milky Way.
Q 04Which Middelburg spectacle-maker filed the earliest known telescope patent application in 1608?
Hans Lippershey
Hans Lippershey. He never got his patent, yet the States General paid him handsomely to make several versions of the instrument built for both eyes.
Q 05The twin Keck telescopes stand near the summit of which Hawaiian volcano?
Mauna Kea
Mauna Kea. Each 10-metre mirror is made of 36 hexagonal segments, which computers nudge back into line twice a second as the telescope turns.
Q 06Galileo, then a professor at nearby Padua, presented his telescope to which city's senate in 1609 and had his salary doubled?
Venice
Venice. He had first heard of the spyglass there earlier that year and, by his own account, worked out how to build one on the night he got home.
Q 07Galileo's lens design, a convex objective with a concave eyepiece, is still used today in which viewing device?
Opera glasses
Opera glasses. The pairing gives an upright image in a short tube, handy in a theatre, but its narrow field of view led astronomers to drop it for a design that shows the sky upside down.
Q 08Which astronomer described in 1611 a telescope with a convex objective and a convex eyepiece?
Johannes Kepler
Johannes Kepler. He only described the design on paper, and it caught on some twenty years later, after the Jesuit Christoph Scheiner built such telescopes and found the view far wider.
Q 09Christiaan Huygens discovered which moon in 1655 with a telescope he built himself?
Titan
Titan. Huygens called it simply 'Luna Saturni', Saturn's moon, and the European probe that parachuted to its surface in 2005 was named Huygens after him.
Q 10What were the very long tubeless refractors of the late 17th century, their lenses mounted on tall poles, called?
Aerial telescopes
Aerial telescopes. Christiaan Huygens set the lens on a high mast and aimed it from the ground with a taut string, since very long focal lengths cut the colour fringes of simple lenses.
Q 11Who built the first practical reflecting telescope in 1668?
Isaac Newton
Isaac Newton. He was convinced that any lens must smear starlight into colours, so he cast and polished a small metal mirror himself and built a telescope only about six inches long.
Q 12What tin-copper alloy was standard for telescope mirrors into the 19th century?
Speculum metal
Speculum metal. It tarnished so quickly that the big telescopes kept a second mirror on hand, to swap in while the first was away being repolished.
Q 13Europe's Very Large Telescope stands on a mountaintop in which desert?
The Atacama
The Atacama. The Chilean desert's high, dry air also drew ALMA, an array of 66 radio dishes on a plateau 5,000 metres above sea level.
Q 21Which French physicist began coating glass telescope mirrors with silver in 1857, independently of a German rival?
Léon Foucault
Léon Foucault. The man behind the famous pendulum showed that a silver film on glass reflected far more light than a metal mirror and could simply be stripped off and renewed when it tarnished.
Q 22The University of Chicago built Yerkes Observatory, with its record 40-inch refracting telescope, in which neighbouring state?
Wisconsin
Wisconsin. Astronomer George Ellery Hale talked Chicago streetcar tycoon Charles Yerkes into paying for the world's largest refractor, and its lens went to Williams Bay in 1897.
Q 23Why do telescope lenses top out near one metre?
They sag under their own weight
Q 14In the Cassegrain reflector, published in 1672, light leaves the tube through what?
A central hole in the main mirror
A central hole in the main mirror. A small convex mirror bounces the light back down through it, packing a long focal length into a short tube, and the layout came to dominate large telescopes.
Q 15Jocelyn Bell found which new kind of object in 1967 as a 'bit of scruff' on her radio telescope's charts?
Pulsars
Pulsars. The pulses came so regularly, every one and a third seconds, that the first one was nicknamed 'little green men'; the Nobel Prize that followed went to others, not to her.
Q 16What does an achromatic lens combine to bring red and blue light to the same focus?
Two kinds of glass
Two kinds of glass. A convex lens of ordinary crown glass spreads the colours apart, and a concave lens of leaded 'flint' glass bends them back together.
Q 17In which 1997 film does an astronomer pick up an alien signal at New Mexico's Very Large Array?
Contact
Contact. The array's 27 working dishes are moved along railway tracks, so they can be spread along arms up to 21 km long to zoom in on fine detail or packed into a patch about a kilometre across.
Q 18Which planet was discovered in 1781 by a musician using a homemade telescope?
Uranus
Uranus. William Herschel first reported it as a comet, and it took about two years for astronomers to agree he had found a new planet, the first ever discovered with a telescope.
Q 19What did William Herschel do in his giant reflectors so that no second mirror was needed?
Tilted the main mirror
Tilted the main mirror. Herschel stood in a cage at the mouth of the tube and looked down at the image directly, a real gain when metal mirrors wasted so much of the light.
Q 20Who built the 72-inch 'Leviathan of Parsonstown', the world's largest telescope for some seventy years from 1845?
Lord Rosse
Lord Rosse. Through it the Irish earl found that some 'nebulae' are spirals, long before anyone knew they were galaxies far beyond our own.
They sag under their own weight. A lens can be gripped only around its rim, while a mirror can be supported across its whole back, which is why the giants of the past century are all reflectors.
Q 24The 100-inch Hooker telescope, the world's largest from 1917 to 1949, is on which California mountain?
Mount Wilson
Mount Wilson. Los Angeles merchant John D. Hooker put up the seed money for the mirror, and with the finished telescope Edwin Hubble found that the universe is expanding.
Q 25The 200-inch Hale Telescope at Palomar has a primary mirror made of which glass?
Pyrex
Pyrex. General Electric first tried and failed to make the disc from fused quartz, so the project turned to Corning's low-expansion glass, sold under a name better known from kitchenware.
Q 26Which country built the six-metre telescope that took the 'world's largest' title from California's Hale Telescope in the 1970s?
The Soviet Union
The Soviet Union. Its BTA, short for 'Big Telescope Alt-azimuth', stands in the Caucasus, and the computer-steered mount in its name became the standard for the giants that followed.
Q 27As William Herschel called down from his telescope, which relative sat at a window recording his observations?
His sister Caroline
His sister Caroline. When William pulled a string she opened the window and wrote down what he shouted, did the calculations by day, and found several comets in sky sweeps of her own.
Q 28Which low-cost telescope design on a simple wooden mount is named after a San Francisco monk who built them from salvage?
The Dobsonian
The Dobsonian. John Dobson made big reflectors from ship portholes and cardboard tubes, lost his place in the monastery over the hobby, and spent decades showing the sky to passers-by.
Q 29Which Bell Labs engineer first detected radio waves from space in 1932?
Karl Jansky
Karl Jansky. Sent to hunt the static that spoiled radio telephone calls, he found a faint hiss that returned four minutes earlier each day, keeping time with the stars and not the Sun.
Q 30Where did engineer Grote Reber build the first dish radio telescope, at his own expense, in 1937?
In his back yard
In his back yard. Reber, of Wheaton, Illinois, used the 31-foot dish to make the first survey of the radio sky, working at night because sparks from passing car engines drowned the signal by day.