Transcript Doppler effect

Astronomy 1020
Stellar Astronomy
Spring_2016
Day-15
Solar Flare
Lab This Week
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Lenses & Telescopes
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What you need to know:
You get to visualize the spectra from various
sources.
Reading ahead in Chapter 6 will help.
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Telescopes
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Telescopes have three functions:
1.
Gather light
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2.
Resolve objects
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3.
LGP ∝ Area = πR2
Θ = 2.06 X 105 (λ/D)
Magnify EXTENDED objects
 Focal length: distance between lens and the
image (longer = larger image).
 Aperture sets the light-collecting power.
 Focal length determines the image size.
Course Announcements
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1st “Hot Topics in Science”: Coming Soon
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Topics this semester are: Human Cloning, Environmental
Toxicology, & Fracking … includes pizza.
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Dark Night Observing: Mon. 2/29 & Wed. 3/2 –
7:30pm at the APSU Observatory
Exam-2 – Fri. 3/4 Chapters 5 & 6
Smartworks Chapters 5 & 6: Due Fri. 3/4
Spring Break Mar. 5-13 (Sat.-Sun.)
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APSU Research and Creativity Forum April 15, 2016
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Abstracts are due: 4:00pm Fri., March 18
Feb. 29 – Last day to drop with an automatic “W”
Apr. 1 – Last day to drop a class with W, F, FA
 The wavelengths at which atoms emit and
absorb radiation form unique spectral
fingerprints for each atom.
 They help determine a star’s composition,
temperature, and more.
 The motion of a light source toward or away
from us changes our perception of the
wavelength of the waves reaching us.
 Doppler effect.
MATH TOOLS 5.2
 If you know the wavelength of light you are
observing as well as the wavelength of light
the object would be emitting if it were at rest,
you can find the speed of the object using
the Doppler effect.
 Light from approaching objects is
blueshifted; the waves crowd together.
 Light from receding objects is redshifted;
the waves are spaced farther apart.
 The motion of a light source toward or away
from us changes our perception of the
wavelength of the waves reaching us.
 Doppler effect.
Lecture Tutorial
Doppler Shift: (pg. 75)
• Work with a partner!
• Read the instructions and questions carefully.
• Discuss the concepts and your answers with one
another. Take time to understand it now!!!!
• Come to a consensus answer you both agree on.
• If you get stuck or are not sure of your answer, ask
another group.