The Tools of Astronomy

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The Tools of Astronomy

• Chapter 15 section 1

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Studying Light

• Light can be reflected, absorbed or transmitted.

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If it is reflected or absorbed, the substance is
opaque (can not be seen through).
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If it is transmitted it is either transparent
(image can be seen clearly) or translucent (image
cannot be seen clearly).
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Transparent
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Translucent
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Light on Mirrors

• Light can be reflected by mirrors through either
• Regular reflection (angle of incidence angle of
  reflection) glare
• Or
• Diffuse reflection (angle of incidence does not
  equal angle of reflection) no glare

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Types of Mirrors

• Flat- wall mirror
• Size of image is same

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Types of Mirrors

• Concave- inward curved surface
• Reflects light rays to a point
• Size of image can be magnified/focused

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Types of Mirrors

• Convex- outward curved surface
• Spread light rays outward
• Size of image always smaller

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Lenses

• Cause light to be refracted
• Refraction- bending of light rays due to a change
  in the medium (substance in which light rays
  travel through)

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Types of Lenses

• Concave- inward curved lens (thicker at edges
  than at center)
• Spreads light rays outward
• Size of image always smaller

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Types of Lenses

• Convex- outward curved lens (thicker in center
  than at edges)
• Bends light rays to a point
• Size of image can be magnified and focused

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Telescopes

• Used for the collection of light

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Types of Telescopes

• Refracting- uses a series of convex lenses
  (objective and an eyepiece lens)

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Types of Telescopes

• Reflecting- uses mirrors (concave and flat) and
  an eyepiece lens (convex)

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Types of Telescopes

• Hubble Space telescope
• clearer pictures because light doesnt have to go
  through Earths atmosphere

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Types of Telescopes

• Radio- concave surfaces collect radio signals
  from deep space

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Satellite Collision
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Studying Light

• Electromagnetic spectrum- range of wavelengths of
  light

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Spectrographs

• Break down the visible spectrum into the
  wavelengths of light that compose the substance
• Based on chemical composition of substance that
  produced the light
• Unique to the substance

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Spectrographs
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Spectral Analysis

• Technique used to compare known spectra to light
  from stars
• Determines composition and temperature of stars
• Inferring activity, page 600 in book