ology logo
card
061

telescope

OLogy Series
tool
card
061

telescope

OLogy Series
tool

Before telescopes were invented, people gazed at the night sky with amazement and dreamed of a closer look. The invention of the telescope in 1608 gave humans their chance to explore the vastness of the Universe. In fact, most of what we know about the Universe comes from studying the sky with telescopes. Telescopes use lenses and mirrors to gather light and produce images. Galileo was the first to use telescopes for astronomy.

Galileo's First Look
Galileo Galilei was the first scientist to use a telescope to look up. What he saw was important because it disproved the notion that everything revolved around Earth. It was thought that Earth was at the center of the Universe and that everything revolved around it. Galileo made many important observations that helped to disprove this. Among other discoveries, he saw that Venus had phases like Earth's Moon. This suggested that Venus was revolving around the Sun, not Earth. He also saw that Jupiter had four moons revolving around it. Galileo saw a lot more stars than are viewable from Earth, and examined the crater-spotted surface of our Moon. Galileo's observations laid the groundwork that helped Newton develop his theories of motion -- laws that explain how different bodies move. Galileo's observations are still repeated by many amateur astronomers today.

What equipment does a reflecting telescope use to help provide information?

lens

mirror

rocket

Are you right?

Correct!

A telescope needs light to help capture information. A reflecting telescope uses a mirror to gather the light that is needed to produce an image.

If you look through a telescope on Earth, the images you see are slightly blurred due to:

dusty mirrors

Earth's atmosphere

Earth's rotation

Are you right?

Correct!

When gazing at the sky through a telescope, the stars and planets have a blurry appearance. Eventually, astronomers put telescopes into orbit around Earth to avoid the blurring effects of the atmosphere.

One of the largest telescopes in the world is larger than a football field.

Fact
or
Fiction
?

Fact

The Arecibo radio telescope in Puerto Rico is 1,000 feet across and has been used to study pulsars, galaxies, and the Universe.

Inventor: Dutch scientist Hans Lippershey
When: 1608
Size of mirror: from a few inches to over 30 feet across
Types: refracting, reflecting, radio, X-ray, microwave, ultraviolet, gamma ray
Significance: telescopes allow humans to observe objects and events throughout the Universe

Image credits: courtesy of AMNH.