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Telescopes are sophisticated instruments that collect light far beyond the capability of the human eye, magnifying tiny images for observation. There are several types of optical telescopes, including refracting telescopes, which use lenses to bend light, and reflecting telescopes that utilize curved mirrors to focus starlight. Notable telescopes like the Hubble and Schmidt telescopes showcase unparalleled resolution. Additionally, radio telescopes capture emissions from celestial bodies. Understanding the electromagnetic spectrum, including the Doppler Effect, enhances our knowledge of celestial movements and compositions.
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Telescopes • They can collect far more light than the unaided eye • They can magnify very small images Different Types of Optical Telescopes (uses lenses and mirrors to gather and focus starlight) 1. refracting telescope – bends or refracts starlight through the first lens to focus the image through the second lens (the eye piece) 2. reflecting telescope – uses one large curved mirror to focus starlight 3. multiple-mirror telescopes – many reflecting mirrors working in unison to produce larger, higher resolution images
Multiple-Mirror Telescope Observatory in Mt. Hopkins, Arizona
Telescopes (cont.)Famous Telescopes Schmidt Telescope – uses both reflecting mirrors and refracting lenses
Telescopes (cont.)Famous Telescopes Hubble Telescope – reflecting telescope orbiting Earth, has unparalleled resolution and usable for ultraviolet detection that is not possible from Earth’s surface
Other Types of Telescopes Spectroscope – uses a prism to separate visible light and determine the chemical composition of a star E.W. Maunder (at the eyepiece) and W. Bowyer observing with the half-prism spectroscope, c. 1894
Arecibo in Puerto Rico (1000’ dia.) Radio Telescope – very large telescope that picks-up radio waves emitted by quasars and pulsars The Very Large Array (VLA) in San Agustin, NM →→→→→
Electromagnetic Spectrum • The elecromagnetic spectrum includes all forms of radiation, 7% of which is visible light -- the radiation to which our eyes are sensitive. • The spectrum up according to the wavelength of the radiation.
Doppler Effect The apparent change in the wavelength due to an object's motion Sound: like the whistle on a train or a car horn as it goes past.
Doppler Effect Red shift – as an object moves away – the wavelength the star radiates gets longer… toward the RED end of the spectrum • The faster the distance increases the greater the ‘Red Shift’ The object is moving away from us
Doppler Effect Blue shift – as an object moves toward – the wavelength the star radiates gets shorter… toward the BLUE end of the spectrum • The faster the distance decreases the greater the ‘Blue Shift’ The object is moving toward US
Parallax the apparent displacement of an observed object due to a change in the position of the observer http://sci2.esa.int/interactive/media/flashes/2_1_1.htm
Parallax http://sci2.esa.int/interactive/media/flashes/2_1_1.htm