Upload
janel-chandler
View
218
Download
0
Embed Size (px)
DESCRIPTION
Telescopes and Domes Optical Telescopes; * use lenses and mirrors to gather and focus starlight. * the light gathering power depends on the area of the lens or mirror. There are 2 types of optical telescopes………..
Citation preview
Telescopes….
Telescopes are helpful to astronomers because they….
• Collect more light• Separate distant objects….• Magnify the image• Detect other wavelengths…
Telescopes and Domes
Optical Telescopes; * use lenses and mirrors to gather and focus
starlight.* the light gathering power depends on the area of the lens or mirror.
There are 2 types of optical telescopes………..
Refracting…• Has two lenses..
• Uses large objective lens to gather and focus light.
• Most in use today are almost 100 years old.
Reflecting telescope…
• Uses one large curved mirror to gather and focus starlight.
MMT multiple-mirror telescope
• This telescope has several mirrors that take the place of one mirror..
• Spectroscope: separates starlight into colors.
3 kinds of visible spectrum…
• Continuous – unbroken band of colors. Source is sending out energy of all wavelengths.
• Bright line – Source is sending out only certain wavelengths of energy. (also called emission spectra)
• Dark-line – continuous spectrum with dark lines. Helps identify composition.
Radio Telescope• Collects radio waves and feeds them to
a receiver, where they are changed into electrical signals.
• What are some advantages that a radio telescope has over an optical???????
Lenses……
• It is a transparent material that bends or refracts light.2 main types of lenses;
• Convex: thick in the middle. Bending light inward. Amount of refraction depends on how curved the lens is.
• Concaved: thin in the middle. Bends light away from the lens. (spreads apart)
Top: a convex lens converges light raysBottom: a concave lens diverges light rays
Images• Real image: one that can be projected
onto a screen. The image is upside down..
• Virtual image: when an object is placed between a convex lens and its focal point producing a larger and upright.
i.e… (magnifying glass)
Space Telescopes
• The Hubble Telescope was designed to take pictures of the whole universe.
• What major advantage does the Hubble have over ground based telescopes?????
Pictures from the Hubble Space Telescope
Doppler Shift (effect)• Sometimes the black lines in a star’s
spectrum are shifted to the Red or Blue end of the spectrum.
• These shifts occur because of a change in the distance between the star and Earth.
• When the distance increases (moving away) = shifted toward the longer wavelength (RED).
• When the distance decreases (moving closer) = shifted toward the shorter wavelength (BLUE).