The Tools of the Astronomer

The Telescope The telescope was invented in 1608. A telescope is a device built to observe distant objects by making them appear closer. Galileo’s telescope

Light Light is a form of electromagnetic radiation. Scientists call the light you can see visible light. Light travels in waves. The distance between the crest of one wave and the crest of the next is called a wavelength.

Visible Light White light shined through a prism spreads out to make a range of different colors with different wavelengths called a spectrum.

Stars produce energy The electromagnetic spectrum includes the entire range of radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, and gamma rays. All of these waves are produced by stars.

The Electromagnetic Spectrum

Telescopes Telescopes collect and focus light and other forms of electromagnetic radiation. A telescope that uses lenses or mirrors to collect and focus visible light is called an optical telescope.

Optical Telescopes There are two major types of optical telescopes: refracting and reflecting.

Types of Telescopes A reflecting telescope uses a curved mirror to collect and focus light. A refracting telescope uses convex lenses to gather and focus light.

What’s the difference? Refractor Reflector Reflects image off a curved mirror Image is right side up Has only lenses Image is upside down (inverted) Uses light to form a visible image

Devices used to detect radio waves from objects in space are called radio telescopes.

Radio Telescopes Most radio telescopes have curved, reflecting surfaces and are located on Earth’s surface. The largest radio telescope is the Arecibo Radio Telescope in Puerto Rico.

Other types of telescopes Other telescopes are designed to detect infrared radiation, ultraviolet radiation, X-rays, or gamma rays. The sun in x-rays

Atmospheric Umbrella Most ultraviolet radiation, X-rays, and gamma rays are blocked by Earth’s atmosphere. To detect these wavelengths, astronomers have placed telescopes in space.

The Hubble Space Telescope space visible light telescope Was put in space in 1990 Produces extremely sharp visible images Also collects ultraviolet and infrared radiation

Kepler Space Telescope http://astroguyz.com/2010/04/21/space-telescopes-part-i-optical/

Looking for other planets

The Spitzer Space Telescope surveys the sky in the infrared range of the spectrum. Was launched into space in 2003

Gamma and X-ray Telescopes On 26 Aug 2008, GLAST was renamed the "Fermi Gamma-ray Space Telescope" in honor of Enrico Fermi, a pioneer in high-energy physics. The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999.

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