A family enjoying the evening sky with binoculars and a telescope.
Image courtesy Wikimedia Commons
What is a Telescope?
With just our eyes, we can see many things in the night sky, including stars, planets, meteors, comets, auroras, and the Moon. Have you ever looked up and wished that you could take a closer look at the Moon or see the rings of Saturn? You have probably seen photographs of distant galaxies, exploding stars, and glowing nebulas. Did you wonder how those photos were taken?
For the past 400 years, telescopes have helped astronomers see into the depths of outer space. Although there are many different types of telescopes, they all work in a similar way. A telescope is an instrument designed to collect electromagnetic radiation for the observation of remote objects. The word “telescope” comes from the Greek words tele=far and skopein=to look or see.
The first known telescope was built by the Dutch lens-maker Hans Lippershey in 1608. Word of this invention spread quickly and by 1609 an Italian scientist named Galileo Galilei built his own and began studying the sky. Galileo made many important discoveries with his new telescope, including craters on the surface of the Moon, four large moons of Jupiter, and the phases of Venus. He used his telescopes to study sunspots, discovering that the Sun rotates on its axis.
Today the word telescope can refer to a whole range of instruments operating in most regions of the electromagnetic spectrum, from the longest radio waves to the shortest gamma rays. They have been placed in the middle of deserts, the top of mountains, and even at the South Pole to better see the sky. The Hubble Space Telescope is just one of many that have been placed in outer space and there are even a few neutrino “telescopes” that are built underground.
Shop Windows to the Universe Science Store!
Our online store
includes fun classroom activities
for you and your students. Issues of NESTA's quarterly journal, The Earth Scientist
are also full of classroom activities on different topics in Earth and space science!
You might also be interested in:
Many people are fascinated by Saturn's rings. Although Saturn isn't the only planet with rings, it is the only planet famous for them. Almost every image or drawing of the planet has the rings included....more
Electromagnetic radiation is the result of oscillating electric and magnetic fields. The wave of energy generated by such vibrations moves through space at the speed of light. And well it should... for...more
Sunspots are dark, planet-sized regions that appear on the "surface" of the Sun. Sunspots are "dark" because they are cooler than their surroundings. A large sunspot might have a central temperature of...more
Radio waves are a type of electromagnetic radiation. A radio wave has a much longer wavelength than does visible light. We use radio waves extensively for communications. Radio waves have wavelengths as...more
The Hubble Space Telescope (HST) was one of the most important exploration tools of the past two decades, and will continue to serve as a great resource well into the new millennium. The HST is credited...more
Hi to all from the IAC80 telescope on the island of Tenerife, hidden away on the Canary Islands. Last month, one of my friends, Katrien, was here and she told you a little about observing stars that pulsate....more
Have you ever seen the Southern or Northern Lights? Did you know that Earth isn't the only planet that puts on these beautiful light shows, also known as the "aurora"? Auroral displays have also been observed...more