Telescopes

Telescopes Key Concepts What are the regions of the electromagnetic spectrum? What are telescopes and how do they work? Where are most large telescopes located?

Telescopes - Key Terms Telescope Electromagnetic radiation Visible light Wavelength Spectrum Optical telescope Refracting telescope Convex lens Reflecting telescope Radio telescope Observatory

Telescope A device that makes distant objects appear to be closer. Galileo made the telescope famous. He was the first to see sunspots, Saturn’s Rings, and the four large moons of Jupiter

Electromagnetic Radiation Energy that can travel through space in the form of waves Examples of Forms of Radiation visible light – radiation you can see infrared – feel as heat radio waves

Ranges from long wavelength radio waves to short wavelength gamma rays

Types of Telescopes Instruments that collect and focus light and other forms of electromagnetic radiation. Optical telescope – uses lenses or mirrors to collect and focus visible light Two types – refracting and reflecting Non-optical – Use other forms of electromagnetic radiation such as radio waves, x-rays and gamma rays

Refracting Telescopes Uses convex lenses to gather and focus light Convex lens is a curved piece of glass that is thicker in the middle than the edges The larger the lens the more light the telescope can collect Simple refracting telescope has 2 lenses – the objective lens and the eyepiece lens Yerkes Telescope in Wisconsin is the largest refracting telescope

Reflecting Telescopes Isaac Newton built the first in 1668 Uses a curved mirror to collect and focus light The larger the mirror, the more light that can be collected Largest optical telescopes today are reflecting

Radio Telescopes Devices used to detect radio waves from objects in space Most have curved reflecting surfaces that focus radio waves the way the mirror does in reflecting telescopes Concentrate the faint radio signals onto small antennas like those on radios Ex. The Very large Array, Arecibo

Other Telescopes Detect: Infrared – Spitzer Space Telescope Ultraviolet X-rays – Chandra X-Ray Observatory Gamma rays Hubble Space Telescope detects visible, ultraviolet, and infrared

Observatories A building that contains one or more telescopes. (some in space) Many large observatories located on mountaintops or in space – atmosphere makes images blurry. Radio telescopes are not affected by atmosphere